My spreadsheet tracks expenses for faculty accounts. They are limited to
$700 for conference travel OR $500 for other research expenses.
I added a column for a code, C for conference and O for other, and used
these formulas to keep a running total of each type of expense:

=SUM(IF((F13:F90)="C",D13:E90))
=SUM(IF((F13:F90)="O",D13:E90))

Now I want to have a formula in cell G8 to show me the remaining funds,
whether the funds have been spent on travel or research. In other words, if
columns D and E (encumbered and actual expenses) total $500 in expeses coded
"O," or total $700 in expenses coded "C," G8 should show zero.
Is this possible? Thank you!