I've been using the following formula:
=SUMPRODUCT(--('Front End'!B$9:B$33<=A8),--('Front End'!C$9:C$33>=A8+"00:15"))

I want to add an additional range from a different tab in that workbook. It seems when I try to add this new tab I get a formula error

This is what I tried(the bold is what I added):

=SUMPRODUCT(--('Front End'!B$9:B$33<=A8),('Combo EE'!B8:B10<=A8)--('Front End'!C$9:C$33>=A8+"00:15"),('Combo EE'!C8:C10>=A8+00:15))