Gary
I have had the same problems in the past and never really found a
satifactory answer to it. I found myself resorting to VLOOKUPs and
"pasteing special values" on top of their own formulas. Not only were
people's pay rates changing but the taxman would change his scales too.

What I am going to do now is calculate this information with a VBA
procedure. So now I do not have to worry about parameters changing.
There are no formulae and I can build conditions in. I havn't needed to
do this yet. But I have done similar things and feel pretty confident
that it will work a treat.

Hope that helps some..... It was great to see a question that I
understood.

Geoff