I've got 2 worksheets in 1 workbook, one labelled PO and one labelled OCR.

In the PO worksheet, I've entered the following formula:
=SUMPRODUCT(--(OCR!A2:A65536=C4),--(OCR!D2:D65536=A1),--(OCR!V2:V65536))

It's only returning a value of £15,674, but it should be returning a value
of £251,537 (when checking the data manually).

I must be missing something with my formula - is there an obvious error?

Thanks