Excel 2010 Pivot Tables

I have created a pivot table with each month as the main category and a product line as the row with the amount sold going into the sub columns (each week) - and the whole year is totaled. but i have hidden the weeks so you can only see the month. i tried adding a percentage on the end of the pivot table - becuase i wanted to see the percentage of each product sold - but everytime i go to "maximise" the weeks in the month the percentage column disappears. So my question is - is there anyway to not to "maximise" all the weeks of each month - then going in manually and hiding them? and be able to show the percentage of each month?

Thanks so much for your help

Can you post a copy of your spreadsheet so we can see how you have your data formatted?