I been experimenting with this all day. What has been happening, for me at least, is that I've been adding things that I knew were covered then I'd call $pcm->covered. The module prints out all the methods that are covered and returns 1. On the other hand, when I call $pcm->uncovered on the things I knew to be uncovered, the module returned undef---it didn't print. I was expecting it to return the uncovered handles. The joys of "PEBKAC hell":).