I have a conditional SUMIFS

Detail Sheet

Type Date Qty
Credit 2/1/10 1
Sales 2/2/10 2
Credit 2/15/10 3

Summary Sheet

Week # Start Date End Date Credits Sales
1 2/1/10 2/5/10 1 2
2 2/8/10 2/15/10 3 0

So, basicallay I am summing the Credit column if the Detail is Type Credit
and the Date is = the Start Date on the line and the End Date <= the Date on
the line. Same for Sales. However, as simple as it seems, it just seems not
lo like the dates.

=SUMIFS(Detail!C:C,Detail!A:A,"=B6",Detail!A:A,"< =C6",Detail!B:B,"Credit")

This keeps summing to 0. When I try testing things other than dates, it
works just fine. I tried sticking a '&' before the B6 and C6 - that did not
work.

Any ideas?