This may be a little confusing, please bear with me.

I need to calculate a total balance, using a column of service dates. The
price per date is the same. This is simple. Problem is, since July 2009 I
need to use a different rate, while retaining the pre-July rate as well in
the total. So is there a way to get a total balance for a column of dates
with two different multipliers?

I was using a simple COUNTA formula for the total number of dates and then
just multiplying that number by my amount. I'm thinking to combine two
counting formulas, one looking for pre-July 2009 dates and multiplying those
by the old price and the second looking for the post-July 2009 dates and
multiplying them by the new price. But I haven't been able to come up with
this yet...

Any help is appreciated.