I think a lot of problems people think they have are just differences in ways of thinking or learning. I've said it elsewhere, but I have a difficult time with memorisation. I can do it, but it seems very hard for me. Some people would learn the notes of a scale on an instrument, then would pick up the instrument and be able to play the scale. If you hand me an instrument, and tell me what a string is tuned to, I'll play a scale, but I'll figure out the names of the notes later, and with a great deal more effort. The scales are instinctive - I know where to put my fingers to make the right sounds. It's as if the music isn't processed in a concious part of my brain.

Jon, it almost sounds like you do the same thing with tempo. You hear it and can play it, but it's a "gut level" thing - you don't think about it, but just do it. You may have to imagine how you play the notes and what they sound like in the tune.