Area calculation problem

[PrawiraV]

Revit has different area calculation for the same boundary

The room area shows 73, but when I trace the boundary with masking region, it shows different result for the area calculation. The difference is about 2 meter square. Can someone explain what I did wrong

room area

masking region area

[barthbradley]

Room area display and calculation are incorrect in Revit | Revit Products 2020 | Autodesk Knowledge ...

[constantin.stroescu · Accepted solution]

have a look at how Area computation is done

[Urfan_MammadovNPHX2]

It is the method of making room area in logic of schedule area. But how to do opposite? I checked manually room area is correct but in schedule wrong. Area of schedule is calculating also area which is under walls. For floor finish material calculation it makes mess. How to solve it?