I have a pivot table showing Field 1 with Sum of Amount where rate is 0 &
Field 2 with Amount*Rate.

I want a third CUSTOM field to show Field 2/Filed 1 so as to calculate the
wieghted average rate; and

a CUSTOM field 4 showing CUSTOM field 3 multiplied by 11% so as to determine
the future budgeted rates.

All guidance & assistance shall be highly appreciated.