ExcelBanter - Specifying the order of pivot table calculated fields/items

Hello,

I have a pivot table that defines both calculated fields as well as a
calculated item. The calculated item looks at the change between two time
periods.

The problem is that excel seems to be calculating the item first. This is
producing incorrect results. Is there a way to specify that I want the field
to calculate first before the item? For example, I have profit and revenue
for two time periods A and B. I calculate a profit margin as profit/revenue
and then want to calculate the change from period A to period B.

profit (a) = 100, profit(b) = 150
rev(a) = 200, rev(b) = 250
%Profit(a) = 100/200 = 50%; %Profit(b) = 150/250 = 60%
Change in profit from a to b = 10% (60%-50%)

However, Excel is doing the following:
Change in Profit = 50
Change in Revenue = 100
Change in Profit % = 50/100 = 50%

Thanks in advance for any help you can provide.