Carim

Many Thanks - that seems to do it - I'll have to study the functions you
have used to understand how they operate. But for now I'll just accept that
they work.

Andrew

"Carim" wrote:

Hi Andrew,

Copy following formula in cell D1 ... and all the way down ...
=SUM(C1:INDIRECT(ADDRESS(SUMPRODUCT(MAX((ROW($C$1: C1))*($C$1:C1="F"))),
3,4)))*IF(OFFSET(C1,1,0)="F",1,0)

HTH