From what I gather, two separate measures for each of the call centers wants to be created, then a third calculated field needs to be created to add the two together.
By creating two fields similar to the following:
if [Cost Center]="AH00077" then [Expenses Amount Wwops] end
if [Cost Center]="AH00235" then [Expenses Amount Wwops] end
Then, create a third calculation similar to this:
sum([Calculation1]) + sum([Calculation2])
Hope this helps!