Greetings Fellow Monk!
In the standing philosophy of "There Is Always More Than One Way To Do It" I found this CPAN module, Math::Round, which should also do what you are looking for. I have included a chunk of example/test code below:

#!/usr/bin/perl -w
use strict;
use Math::Round;
my $number=1100.64686081907;
$number=nearest(.01,$number);
print "$number\n";
___OUTPUT___
  1100.65
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