If you want to multiply the actual cost by the actual % cost and then compare it to the planned total cost to get the variance, you have to create a new measure that calculates ( Actual cost * Actual Cost % ) and then use it in the comparison.
To do so, click on the “Table Tools” menu, then choose Quick Measure.
You can also add a quick measure by clicking on the 3 dots in any data column and choose add quick measure.
A new window will open, choose “Multiplication” from the calculation menu.
Drang and drop the two data columns that you want to multiply them.
Finally, click Add, It will appear in the data section, you can then use it to calculate the variance.