A Google user group has apparently started to uncover a surprisingly large number of related bugs in Excel 2007. The bug seems to take most, perhaps all, multiplications problems that would result in the answer 65535 and displays the answer 100000 instead.
The bug doesn't just stop there, there are times when doing further operations on a 'bugged' cell will result in correct results and times where it won't:
There appears to be further bugs that spring from this one. For example:
“What's even stranger is this:
Suppose the formula is in A1.
=A1+1 returns 100001, which appears to show the formula is in fact 100000
and a very Serious problem.
And if you multiply be say, 2 you get something else:
returns 131070, as if A1 had 65535. (which it should have been)
Keeps it at 100000.
=A1-1 returns 65534
=A1/1 is still 100000
=A1/2 retuns 32767.5
Using MAX() on a range appears not to see 100000.”
It should go without saying that if your company uses Excel in your payroll department or anything else that is mission critical, you might want to double check any calculations that could result in 65535.