Thanks Biff.

I put the parantheses in and my values still don't match my colleague's but
I'm beginning to think that maybe my function is fine but HER calculations
aren't.

But just to make absolutly sure, there really shouldn't be any problem with
the function no matter how many ISNUMBER(MATCH I put in? In one cell I'm
going to need to insert four of them.

That's a great tip about naming the array, too. It cuts out a lot of typing
and typo potential. Thank you very much for that suggestion. :)