This should be simple, but its defeating me.

Column A is a date, Column C is text, Column F is a number, and column G is
=IF(C10="Sales",F10/9,"")

In a separate worksheet, a SUMPRODUCT formula works fine to add up the
values in Column F where they fall between two dates (entered in D2 and G2),
i.e:

=SUMPRODUCT(--('Sales&Income'!$F$10:$F$24),--('Sales&Income'!$A$10:$A$24=($D$2)),--('Sales&Income'!A10:A24<=($G$2)))

I also want to sum the aforementioned Column G for the same date parameters,
but
=SUMPRODUCT(--('Sales&Income'!$G$10:$G$24),--('Sales&Income'!$A$10:$A$24=($D$2)),--('Sales&Income'!A10:A24<=($G$2)))
returns #VALUE!

I suspect it is doing this because it doesnt like the €˜value if false
result ("") of the =IF(C10="Sales",F10/9,"") formula. Is there a way to get
around it?

Many thanks!