crosstab summary

[mprof]

I have a crosstab (columns are products - let's say: p1,p2,p3,p4,p5. rows are months starting January).
the measure is 'revenues'. one of the columns is average revenue for each month.
and the last row is total for the entire year.
the problem is that it's also summarize the average column and not calculate the total average.
for example:
if in September i had for p1 revenue of 100 and for August p1 had 200 then the average for September is:3.33 and for August is: 6.45.

i want the total to be 4.91 meaning:(200+100)/(31+30).
the summarize button is adding the averages.
how can i change the cells to have layout calculation or something like that.


thanks for the help