Hrm, that's what I get, too. So why doesn't the imprecision show up when you print the variables out?

Because print doesn't print the full precision of its args. That's what printf is for:

$ perl585 -e'print 26.6+0.2, "\n"'
26.8
$ perl585 -e'printf "%.20f\n ", 26.6+0.2'
26.80000000000000071054
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Dave.