I have data where the exact option of Application.Match always returns
Error when (even when there's a match) and the less-than-exact option
of Application.Match always returns true (even when there's not a
match).

I have the following clip of code:

'less-than-exact option
res = Application.Match(Trim(ad.Cells(i, 1).Value, PSKeyRng)

'exact option
res = Application.Match(ad.Cells(i, 1).Value, PSKeyRng, 0)

So I'm not able to use Application.Match reliably on cells that begin
with "C00".

Can someone suggest an alternative to Application.Match or provide a
few pointers on what could be going wrong?

Thanks.