Some things to bear in mind:
"Last Skipped" and "Skip Count" are updated if you punt the song before it is 50% played. If you punt the song after that, it will be considered as played, and the last played/number plays fields are updated instead.
Also, remember, that if you stop a track, because, say, you have to go out, and it is less than 50% played, that will also count as a skip.
The fields can be useful as a loose guide, but there is a fair amount of fuzziness introduced by the above.
-marko