Adding to the problem is the fact that traditional music in particular does not adhere to "strict" notational timing. For example, hornpipes are generally written as eighth notes, but are played with an emphasis on the first note in each pair. Not enough to rate a dotted eighth and sixteenth, but enough to feel. This is one reason that classically-trained players have trouble getting the right feel to their playing. Jig rhythms can be problematic as well, but the difference is more subtle and can even have regional variations.

Could this be part of the difficulty you're having, Jon?

jeffp