Thank you for your response, MTH. I am working with your formula now. In the meantime, I devised a much less elegant formula that seems to accomplish what I want.

For the "P/T" and "O," it looks like the following (for the 8th or 23rd of the month):

=(IF(AND(OR(DAY(('Expense Report Page 2'!A23))=8,DAY(('Expense Report Page 2'!A23))=23),OR('Expense Report Page 2'!C23="P/T",'Expense Report Page 2'!C23="O")),'Expense Report Page 2'!B23,0))+(IF(AND(OR(DAY(('Expense Report Page 2'!A24))=8,DAY(('Expense Report Page 2'!A24))=23),OR('Expense Report Page 2'!C24="P/T",'Expense Report Page 2'!C24="O")),'Expense Report Page 2'!B24,0))+(IF(AND(OR(DAY(('Expense Report Page 2'!A25))=8,DAY(('Expense Report Page 2'!A25))=23),OR('Expense Report Page 2'!C25="P/T",'Expense Report Page 2'!C25="O")),'Expense Report Page 2'!B25,0))+ (...) and so on, for all of the rows in question.

I don't mind using this one, but yours looks much simpler and I look forward to giving it a whirl.

Thanks again!

-CA