I have a simple table with a quantity in column F that totals 89 items. When I try to summarise the individual items to be purchased my SUMPRODUCT formulas don't give the right answers.

I have simplified my formula to test column F only, like this:
=SUMPRODUCT(--(F7:F192>0))
but the result I get is 55.

Does anyone have any suggestions why this simple formula might not work correctly, please?

Thanks in anticipation!