Hi James

Just for my own interest, i corrected my original sumproduct formula
following advice from the other posters:

=SUMPRODUCT(((weekscurrent-26)*(weeks<=current)+(weekscurrent+26))*(B6:B57))

I've put a bracket around the whole set of conditions, replaced one *
with + (meaning OR), and corrected an error in the 3rd condition. This
should now work.

I thought the first two conditions should be bracketed (they are
AND'd), but the * symbol looks like it has a higher priority than the +
symbol, so brackets are not required.

Regards
Mike


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