Problems with mutiplying 2 dynamic columns (from pivottable with variating columns)

Hi, I want to multiply 2 columns. I need to calculate both columns from 2 different positions. Columns 1 has a fixed position, but column 2 varies in position.

Column1 = 4
Column2 = Mylastcolumn+3


This is what I have:

Please Login or Register  to view this content.

Do I need to use OFFSET? Or can it be solved in a other way?

Any comment on this? thanks in advance!