Try using this:

=((M9472-SUMIF(O2:O9470,"wave",M2:M9470))/(N9472-SUMIF(O2:O9470,"wave",N2:N9470)))*8


Y E S !!

I'm a little embarassed at how long it took me to see it even when I had your solution for comparison..

It's amazing that moving one parenthesis can change the answer by a factor of more than six billion!

And, looking at it now, we can actually get rid of the first open and final closing parentheses as well:

=(M9472-SUMIF(O2:O9470,"wave",M2:M9470))/(N9472-SUMIF(O2:O9470,"wave",N2:N9470))*8

I banged my head against my original (incorrect) formula for about three hours before finally coming here and asking for help. I'm impressed!

edit:

I plugged my actual numbers into your "what's actually going on" formula:

(I tried to paste that in here, but it didn't format correctly... how did you manage to write that post with the leading spaces in the lines?)

and the number came out to within 2 KB/Sec of the ridiculous number I was getting (the 523x10^9 number). I bet that really is a rounding error. I mean, a difference of one part in 260 billion is pretty negligible...

tanstaafl.