patch changes don't change

[j.bargar]

I know I've seen posts about this on here, but I can't seem to find them now. Maybe someone can point me in the right direction.

I have imported a couple hundred MIDI files into my SC and am working through them one at a time to create backing tracks for a two piece band (I'm a guitar player, not a keyboard guy). On some songs, when I change patches, the changes are saved for all time thereafter. However, on some songs, I change the patch, and as soon as I exit out of the song and go back to it, the patch is completely different.

What boneheaded noob mistake am I making? Is it as simple as pressing save somewhere?

Thanks in advance,

James