diff --git a/src/ifc5d/Ex8 - BoQ with formula.csv b/src/ifc5d/Ex8 - BoQ with formula.csv
new file mode 100644
index 0000000000..a3e8d77b60
--- /dev/null
+++ b/src/ifc5d/Ex8 - BoQ with formula.csv	
@@ -0,0 +1,14 @@
+Index,Identification,Name,Unit,Value,Quantity,Query,Property,Formula
+1,E.01,Walls,m3,,,,,
+2,E.01.01,Ground floor walls,m3,100,,"IfcWall, location=""Ground Floor""",GrossVolume,
+2,E.01.02,First floor walls,m3,200,,"IfcWall, location=""First Floor""",GrossVolume,
+1,A.02,Paintings,m2,,,,,
+2,A.03,Paintings with water,m2,,,,,
+3,B.05,White paintings,m2,25,,IfcWall,GrossVolume,
+3,B.06,Colored paintings,m2,32,33,,,
+3,B.07,Double paintings,m,,,IfcWall,,NetSideArea*2
+2,C-01,Paintings with machine,m2,17,133,,,
+2,C-02,Decorated paintings,m2,40,8,,,
+1,D,Reinforcements,,,,,,
+2,D.1,Walls reinforcements weight,kg,,,IfcWall,,Pset_ConcreteElementGeneral.ReinforcementVolumeRatio * GrossVolume
+2,D.2,Beams reinforcements weight,kg,,,,,
diff --git a/src/ifc5d/README.md b/src/ifc5d/README.md
index ba37664a88..0c57785236 100644
--- a/src/ifc5d/README.md
+++ b/src/ifc5d/README.md
@@ -39,6 +39,7 @@ See example files as a CSV file format reference:
 - Ex5 - SoR_with_description.csv (a simple SoR with description column)
 - Ex6 - BoQ with categories.csv (a simple BoQ with categories columns)
 - Ex7 - BoQ with Rates.csv (a simple BoQ that connect to an existing SoR. It needs an already loaded SoR.)
+- Ex8 - Boq with formula.csv (a simple BoQ with formula field used to calculate quantities when specified)
 - `sample_cost_schedule_house_FR.csv` / `.ods`
 - `schedule.csv`, `rates.csv` (schedule of rates example)
 
diff --git a/src/ifc5d/ifc5d/csv2ifc.py b/src/ifc5d/ifc5d/csv2ifc.py
index aaab6c7ab1..d43eb907e9 100644
--- a/src/ifc5d/ifc5d/csv2ifc.py
+++ b/src/ifc5d/ifc5d/csv2ifc.py
@@ -412,16 +412,13 @@ class Csv2Ifc:
                 results = ifcopenshell.util.selector.filter_elements(self.file, cost_item["Query"])
                 results = [r for r in results]
                 ifc_quantity_class = ifcopenshell.util.unit.get_symbol_quantity_class(cost_item["Unit"])
-                try:
-                    quantity = ifcopenshell.api.cost.assign_cost_item_quantity(
-                        self.file,
-                        cost_item=cost_item["ifc"],
-                        products=results,
-                        formula=cost_item["Formula"],
-                        ifc_class=ifc_quantity_class,
+                quantity = ifcopenshell.api.cost.assign_cost_item_quantity(
+                    self.file,
+                    cost_item=cost_item["ifc"],
+                    products=results,
+                    formula=cost_item["Formula"],
+                    ifc_class=ifc_quantity_class,
                     )
-                except:
-                    quantity=0
 
         self.create_cost_items(cost_item["children"], cost_item["ifc"])
 
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 7a57372e8b..6eb752aef2 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
@@ -23,6 +23,7 @@ from typing import Any
 
 import ifcopenshell.api.control
 import ifcopenshell.api.cost
+import ifcopenshell.util.element
 
 
 def assign_cost_item_quantity(
@@ -142,15 +143,18 @@ class Usecase:
                         variables_modified[v] = self.get_value_from_pset(product, v, separator)
                     else:
                         variables_modified[v] = self.get_value_from_qset(product, v)
+                    if variables_modified[v] == 0:
+                        print(f"WARNING: {product.Name} hasn't the variable {v.replace(separator, '.')}")
 
                 formula_modified = self.settings["formula"].replace(".", separator)
                 if any(v is None for v in variables_modified.values()):
                     for k, v in variables_modified.items():
                         if v == None:
                             print(f"Property {k.replace(separator, '.')} not found")
-                    raise ValueError("Formula contains variables that are not found in properties. Please check the output")
-
-                result = eval(formula_modified, {}, variables_modified)
+                    print("Formula contains variables that are not found in Psets or Qsets. Please check the output")
+                    result = 0
+                else:
+                    result = eval(formula_modified, {}, variables_modified)
 
                 new_quantity = None
                 for quantity in self.quantities:
@@ -231,26 +235,19 @@ class Usecase:
             v: str,
             separator: str,
     ) -> float:
-        for relationship in product.IsDefinedBy:
-            if relationship.is_a("IfcRelDefinesByProperties"):
-                pset = relationship.RelatingPropertyDefinition
-                if pset.Name == v.split(separator)[0]:
-                    for prop in pset.HasProperties:
-                        if prop.Name.lower() == v.split(separator)[1].lower():
-                            return prop[2].wrappedValue
+        pset_name = v.split(separator)[0]
+        pset = ifcopenshell.util.element.get_pset(product, pset_name)
+        pset_property_name = v.split(separator)[1]
+        return (pset or {}).get(pset_property_name,0)
 
     def get_value_from_qset(
             self,
             product:ifcopenshell.entity_instance,
             v: str,
     ) -> float:
-        for relationship in product.IsDefinedBy:
-            if relationship.is_a("IfcRelDefinesByProperties"):
-                qto = relationship.RelatingPropertyDefinition
-                if qto.is_a("IfcElementQuantity"):
-                    for prop in qto.Quantities:
-                        if prop.is_a("IfcPhysicalSimpleQuantity") and prop.Name.lower() == v.lower():
-                            return prop[3]
+        qtos = ifcopenshell.util.element.get_psets(product, qtos_only = True)
+        quantities = next(iter(qtos.values()), {})
+        return (quantities or {}).get(v,0)
 
 class VariableExtractor(ast.NodeVisitor):
     def __init__(self):