Advise on result row calculation in bex query ?

Hi,

I would like to know if we will be able to cal the values from the result row's from 2 columns. Please find the below screenshot.

We need,

1) In column "Actual Payment Nb days" we should have the average instead of the sum : have 58.5 instead of 117. Calculation = (62+55)/2 = 58.50

2). In column "Weighted Average Actual Payment nb days" we should have the weighted average calculation : 59.04 instead of 2

Calculation = (1491.36x62) + (1092.42x55) = 152547.42 divided by (1491.36+1092.42) = 2583.78 so as an weighted average is 59.04 .

I believe we need to use exception aggregation with respective to the vendor, as vendor is the only field in rows. Please advise.

Thanks

DR