Thanks Bob. I really only started this over some curiosity about the behaviour of some of the midi files I had been playing. That drove me to look at the format and then I sort of got sucked in even more and its diverted me completely away from what I was doing in the first place.
The information I have been given on so far has helped a lot. I don't know why I get hung up on stuff like this because it is not that important since I can now achieve what I want to. But... it seems to be that itch I need to scratch.

Thanks