You should be aware of what sort of rounding you are doing. I got into nasty trouble once confusing mathematician's rounding with accountancy rounding. Maths rounds .5 up or down, depending on whether the integer part is odd or even, in order to avoid statistical bias. Accountancy always rounds .5 up.

I don't know if there is a module for accountancy rounding; I ended up using

$toround =~ /\.(\d)/;
if ($1 >= 5) { $toround+=.5 }
$toround = int $toround;
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which is probably pretty fugly, but did the job.

Update Duh, and it uses int(). Excuse my idiocy.
Dave