Beleive me or not, I got different results when set $[ to 1, 7 and 0 running your piece of code. (slightly modified, but you did not provided exact code to execute. and I'll show you my logs if needed.)

About usage of "$_" variable -- beware, your "while(<FILE>)" - this loop corrupts "$_", and "local $_;" statement somewhere before that loop will be a good idea, just to preserve its value.

Sins of Perl Revisited will get you an idea what I mean. Here's an excelent explanation about power plant... well, read on, this certainly worth it!

Jim