diff --git a/src/blenderbim/blenderbim/bim/ifc.py b/src/blenderbim/blenderbim/bim/ifc.py
index e779befc27..c5d9f65d78 100644
--- a/src/blenderbim/blenderbim/bim/ifc.py
+++ b/src/blenderbim/blenderbim/bim/ifc.py
@@ -183,7 +183,7 @@ class IfcStore:
     def commit_link_element(data):
         obj = bpy.data.objects.get(data["obj"])
         IfcStore.id_map[data["id"]] = obj
-        if data["guid"]:
+        if "guid" in data:
             IfcStore.guid_map[data["guid"]] = obj
         blenderbim.bim.handler.subscribe_to(obj, "mode", blenderbim.bim.handler.mode_callback)
         blenderbim.bim.handler.subscribe_to(obj, "name", blenderbim.bim.handler.name_callback)
diff --git a/src/blenderbim/blenderbim/bim/module/cost/operator.py b/src/blenderbim/blenderbim/bim/module/cost/operator.py
index 96bd5cd595..a23f8caa23 100644
--- a/src/blenderbim/blenderbim/bim/module/cost/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/cost/operator.py
@@ -637,10 +637,10 @@ class EnableEditingCostItemValue(bpy.types.Operator):
         data = Data.cost_values[self.cost_value]
 
         blenderbim.bim.helper.import_attributes(
-            data["type"], 
-            self.props.cost_value_attributes, 
-            data, 
-            lambda name, prop, data: self.import_attributes(name, prop, data, context)
+            data["type"],
+            self.props.cost_value_attributes,
+            data,
+            lambda name, prop, data: self.import_attributes(name, prop, data, context),
         )
         return {"FINISHED"}
 
@@ -715,8 +715,8 @@ class EditCostValue(bpy.types.Operator):
     def _execute(self, context):
         props = context.scene.BIMCostProperties
         attributes = blenderbim.bim.helper.export_attributes(
-            props.cost_value_attributes, 
-            lambda attributes, prop: self.export_attributes(attributes, prop, context))
+            props.cost_value_attributes, lambda attributes, prop: self.export_attributes(attributes, prop, context)
+        )
         self.file = IfcStore.get_file()
         ifcopenshell.api.run(
             "cost.edit_cost_value",
diff --git a/src/blenderbim/blenderbim/bim/module/cost/prop.py b/src/blenderbim/blenderbim/bim/module/cost/prop.py
index 94d05993b2..6530781763 100644
--- a/src/blenderbim/blenderbim/bim/module/cost/prop.py
+++ b/src/blenderbim/blenderbim/bim/module/cost/prop.py
@@ -79,7 +79,7 @@ def update_schedule_of_rates(self, context):
     bpy.ops.bim.load_schedule_of_rates(cost_schedule=int(self.schedule_of_rates))
 
 
-def getQuantityTypes(self, context):
+def get_quantity_types(self, context):
     global quantitytypes_enum
     if len(quantitytypes_enum) == 0 and IfcStore.get_schema():
         quantitytypes_enum.extend(
@@ -91,7 +91,7 @@ def getQuantityTypes(self, context):
     return quantitytypes_enum
 
 
-def getProductQuantityNames(self, context):
+def get_product_quantity_names(self, context):
     global productquantitynames_enum
     global productquantitynames_count
     ifc_file = IfcStore.get_file()
@@ -115,7 +115,7 @@ def getProductQuantityNames(self, context):
     return productquantitynames_enum
 
 
-def getProcessQuantityNames(self, context):
+def get_process_quantity_names(self, context):
     global processquantitynames_enum
     global processquantitynames_id
     ifc_file = IfcStore.get_file()
@@ -137,7 +137,7 @@ def getProcessQuantityNames(self, context):
     return processquantitynames_enum
 
 
-def getResourceQuantityNames(self, context):
+def get_resource_quantity_names(self, context):
     global resourcequantitynames_enum
     global resourcequantitynames_id
     ifc_file = IfcStore.get_file()
@@ -166,7 +166,7 @@ def update_active_cost_item_index(self, context):
         bpy.ops.bim.load_cost_item_quantities()
 
 
-def updateCostItemIdentification(self, context):
+def update_cost_item_identification(self, context):
     props = context.scene.BIMCostProperties
     if not props.is_cost_update_enabled or self.identification == "XXX":
         return
@@ -182,7 +182,7 @@ def updateCostItemIdentification(self, context):
         attribute.string_value = self.identification
 
 
-def updateCostItemName(self, context):
+def update_cost_item_name(self, context):
     props = context.scene.BIMCostProperties
     if not props.is_cost_update_enabled or self.name == "Unnamed":
         return
@@ -199,8 +199,8 @@ def updateCostItemName(self, context):
 
 
 class CostItem(PropertyGroup):
-    name: StringProperty(name="Name", update=updateCostItemName)
-    identification: StringProperty(name="Identification", update=updateCostItemIdentification)
+    name: StringProperty(name="Name", update=update_cost_item_name)
+    identification: StringProperty(name="Identification", update=update_cost_item_identification)
     ifc_definition_id: IntProperty(name="IFC Definition ID")
     has_children: BoolProperty(name="Has Children")
     is_expanded: BoolProperty(name="Is Expanded")
@@ -229,10 +229,10 @@ class BIMCostProperties(PropertyGroup):
     active_cost_item_index: IntProperty(name="Active Cost Item Index", update=update_active_cost_item_index)
     cost_item_attributes: CollectionProperty(name="Task Attributes", type=Attribute)
     contracted_cost_items: StringProperty(name="Contracted Cost Items", default="[]")
-    quantity_types: EnumProperty(items=getQuantityTypes, name="Quantity Types")
-    product_quantity_names: EnumProperty(items=getProductQuantityNames, name="Product Quantity Names")
-    process_quantity_names: EnumProperty(items=getProcessQuantityNames, name="Process Quantity Names")
-    resource_quantity_names: EnumProperty(items=getResourceQuantityNames, name="Resource Quantity Names")
+    quantity_types: EnumProperty(items=get_quantity_types, name="Quantity Types")
+    product_quantity_names: EnumProperty(items=get_product_quantity_names, name="Product Quantity Names")
+    process_quantity_names: EnumProperty(items=get_process_quantity_names, name="Process Quantity Names")
+    resource_quantity_names: EnumProperty(items=get_resource_quantity_names, name="Resource Quantity Names")
     active_cost_item_quantity_id: IntProperty(name="Active Cost Item Quantity Id")
     quantity_attributes: CollectionProperty(name="Quantity Attributes", type=Attribute)
     cost_types: EnumProperty(
diff --git a/src/blenderbim/blenderbim/bim/module/cost/ui.py b/src/blenderbim/blenderbim/bim/module/cost/ui.py
index 12d5deaecc..18ea7cd3f6 100644
--- a/src/blenderbim/blenderbim/bim/module/cost/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/cost/ui.py
@@ -373,11 +373,29 @@ class BIM_PT_cost_item_quantities(Panel):
         # Column1
         col = grid.column()
 
+        has_quantity_names = CostProp.get_product_quantity_names(self, context)
+
         row2 = col.row(align=True)
         row2.label(text="Elements")
         op = row2.operator("bim.select_cost_item_products", icon="RESTRICT_SELECT_OFF", text="")
         op.cost_item = cost_item.ifc_definition_id
 
+        if context.selected_objects:
+            if has_quantity_names:
+                op = row2.operator("bim.assign_cost_item_quantity", text="", icon="PROPERTIES")
+                op.related_object_type = "PRODUCT"
+                op.cost_item = cost_item.ifc_definition_id
+                op.prop_name = self.props.product_quantity_names
+
+            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
+            op.related_object_type = "PRODUCT"
+            op.cost_item = cost_item.ifc_definition_id
+            op.prop_name = ""
+
+            op = row2.operator("bim.unassign_cost_item_quantity", text="", icon="REMOVE")
+            op.cost_item = cost_item.ifc_definition_id
+            op.related_object = 0
+
         row2 = col.row()
         row2.template_list(
             "BIM_UL_cost_item_quantities",
@@ -388,23 +406,32 @@ class BIM_PT_cost_item_quantities(Panel):
             "active_cost_item_product_index",
         )
 
-        row2 = col.row(align=True)
-        row2.prop(self.props, "product_quantity_names", text="")
-        op = row2.operator("bim.unassign_cost_item_quantity", text="", icon="REMOVE")
-        op.cost_item = cost_item.ifc_definition_id
-        op.related_object = 0
-        if CostProp.productquantitynames_enum:
-            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
-            op.related_object_type = "PRODUCT"
-            op.cost_item = cost_item.ifc_definition_id
-            op.prop_name = self.props.product_quantity_names
+        if has_quantity_names:
+            row2 = col.row()
+            row2.prop(self.props, "product_quantity_names", text="")
 
         # Column2
         col = grid.column()
 
+        has_quantity_names = CostProp.get_process_quantity_names(self, context)
+
         row2 = col.row(align=True)
         row2.label(text="Tasks")
 
+        tprops = context.scene.BIMTaskTreeProperties
+        wprops = context.scene.BIMWorkScheduleProperties
+        if tprops.tasks and wprops.active_task_index < len(tprops.tasks):
+            if has_quantity_names:
+                op = row2.operator("bim.assign_cost_item_quantity", text="", icon="PROPERTIES")
+                op.related_object_type = "PROCESS"
+                op.cost_item = cost_item.ifc_definition_id
+                op.prop_name = self.props.process_quantity_names
+
+            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
+            op.related_object_type = "PROCESS"
+            op.cost_item = cost_item.ifc_definition_id
+            op.prop_name = ""
+
         row2 = col.row()
         row2.template_list(
             "BIM_UL_cost_item_quantities",
@@ -415,20 +442,32 @@ class BIM_PT_cost_item_quantities(Panel):
             "active_cost_item_process_index",
         )
 
-        row2 = col.row(align=True)
-        row2.prop(self.props, "process_quantity_names", text="")
-        if CostProp.processquantitynames_enum:
-            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
-            op.related_object_type = "PROCESS"
-            op.cost_item = cost_item.ifc_definition_id
-            op.prop_name = self.props.process_quantity_names
+        if has_quantity_names:
+            row2 = col.row()
+            row2.prop(self.props, "process_quantity_names", text="")
 
         # Column3
         col = grid.column()
 
+        has_quantity_names = CostProp.get_resource_quantity_names(self, context)
+
         row2 = col.row(align=True)
         row2.label(text="Resources")
 
+        rtprops = context.scene.BIMResourceTreeProperties
+        rprops = context.scene.BIMResourceProperties
+        if rtprops.resources and rprops.active_resource_index < len(rtprops.resources):
+            if has_quantity_names:
+                op = row2.operator("bim.assign_cost_item_quantity", text="", icon="PROPERTIES")
+                op.related_object_type = "RESOURCE"
+                op.cost_item = cost_item.ifc_definition_id
+                op.prop_name = self.props.resource_quantity_names
+
+            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
+            op.related_object_type = "RESOURCE"
+            op.cost_item = cost_item.ifc_definition_id
+            op.prop_name = ""
+
         row2 = col.row()
         row2.template_list(
             "BIM_UL_cost_item_quantities",
@@ -439,14 +478,9 @@ class BIM_PT_cost_item_quantities(Panel):
             "active_cost_item_resource_index",
         )
 
-        row2 = col.row(align=True)
-        row2.prop(self.props, "resource_quantity_names", text="")
-        if CostProp.resourcequantitynames_enum:
-            op = row2.operator("bim.assign_cost_item_quantity", text="", icon="ADD")
-            op.related_object_type = "RESOURCE"
-            op.cost_item = cost_item.ifc_definition_id
-            op.prop_name = self.props.resource_quantity_names
-
+        if has_quantity_names:
+            row2 = col.row()
+            row2.prop(self.props, "resource_quantity_names", text="")
 
 class BIM_PT_cost_item_rates(Panel):
     bl_label = "IFC Cost Item Rates"
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
index dff2d825a0..744409687d 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_item_quantity.py
@@ -14,8 +14,10 @@ class Usecase:
         # This is a bold assumption
         # https://forums.buildingsmart.org/t/how-does-a-cost-item-know-that-it-is-counting-a-controlled-product/3564
         if self.settings["ifc_class"] == "IfcQuantityCount" and self.settings["cost_item"].Controls:
+            count = 0
             for rel in self.settings["cost_item"].Controls:
-                quantity[3] += len(rel.RelatedObjects)
+                count += len(rel.RelatedObjects)
+            quantity[3] = count
         quantities = list(self.settings["cost_item"].CostQuantities or [])
         quantities.append(quantity)
         self.settings["cost_item"].CostQuantities = quantities
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
index 21f4447383..41518aa011 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/assign_cost_item_quantity.py
@@ -9,7 +9,8 @@ class Usecase:
             self.settings[key] = value
 
     def execute(self):
-        self.quantities = set(self.settings["cost_item"].CostQuantities or [])
+        if self.settings["prop_name"]:
+            self.quantities = set(self.settings["cost_item"].CostQuantities or [])
         for product in self.settings["products"]:
             ifcopenshell.api.run(
                 "control.assign_control",
@@ -17,8 +18,12 @@ class Usecase:
                 related_object=product,
                 relating_control=self.settings["cost_item"],
             )
-            self.add_quantity_from_related_object(product)
-        self.settings["cost_item"].CostQuantities = list(self.quantities)
+            if self.settings["prop_name"]:
+                self.add_quantity_from_related_object(product)
+        if self.settings["prop_name"]:
+            self.settings["cost_item"].CostQuantities = list(self.quantities)
+        else:
+            self.update_cost_item_count()
 
     def add_quantity_from_related_object(self, element):
         if not element.is_a("IfcObject"):
@@ -33,3 +38,21 @@ class Usecase:
         for prop in qto.Quantities:
             if prop.is_a("IfcPhysicalSimpleQuantity") and prop.Name.lower() == self.settings["prop_name"].lower():
                 self.quantities.add(prop)
+
+    def update_cost_item_count(self):
+        # This is a bold assumption
+        # https://forums.buildingsmart.org/t/how-does-a-cost-item-know-that-it-is-counting-a-controlled-product/3564
+        if not self.settings["cost_item"].CostQuantities:
+            return ifcopenshell.api.run(
+                "cost.add_cost_item_quantity",
+                self.file,
+                cost_item=self.settings["cost_item"],
+                ifc_class="IfcQuantityCount",
+            )
+        if len(self.settings["cost_item"].CostQuantities) == 1:
+            quantity = self.settings["cost_item"].CostQuantities[0]
+            if quantity.is_a("IfcQuantityCount"):
+                count = 0
+                for rel in self.settings["cost_item"].Controls:
+                    count += len(rel.RelatedObjects)
+                quantity[3] = count
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py b/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
index ec652a0e10..ed7b555d77 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/unassign_cost_item_quantity.py
@@ -19,7 +19,6 @@ class Usecase:
                         if related_object in self.settings["products"]:
                             self.quantities.remove(quantity)
         self.settings["cost_item"].CostQuantities = list(self.quantities)
-
         for product in self.settings["products"]:
             ifcopenshell.api.run(
                 "control.unassign_control",
@@ -27,3 +26,15 @@ class Usecase:
                 related_object=product,
                 relating_control=self.settings["cost_item"],
             )
+        self.update_cost_item_count()
+
+    def update_cost_item_count(self):
+        # This is a bold assumption
+        # https://forums.buildingsmart.org/t/how-does-a-cost-item-know-that-it-is-counting-a-controlled-product/3564
+        if len(self.settings["cost_item"].CostQuantities) == 1:
+            quantity = self.settings["cost_item"].CostQuantities[0]
+            if quantity.is_a("IfcQuantityCount"):
+                count = 0
+                for rel in self.settings["cost_item"].Controls:
+                    count += len(rel.RelatedObjects)
+                quantity[3] = count