Referencing formula dates in a COUNTIFS statement

Question

I have a set of dates on a sheet made of variations of the following formula:

Where C1 is: =DATE(YEAR(B1),MONTH(B1),DAY(B1)+8)

And B1 is: 01/11/2013 in date format.

I'm trying to reference the cells in a COUNTIFS statement, to avoid having to type the date in each time, but it doesn't seem to register. The full statement looks like this:

=COUNTIFS(Data!$BL:$BL, A7, Data!$BP:$BP, ">=C1",Data!$BP:$BP, "<D1")

Any idea what I'm getting wrong here?

Answer 1

Does this version suit?:

=COUNTIFS(Data!$BL:$BL,A7,Data!$BP:$BP,">="&C1,Data!$BP:$BP,"<"&D1)