Are you sure you're trimming them all off in your micro-trims? Because if not, then they're probably traveling up the shaft.
That said, I think a year and a half is a long time with no real trim, even on CG. I could easily be wrong. But summer 2004 was a long time ago, from the perspective of your ends. You could be doing nothing wrong, everything right, and have some bad ends after a year and a half.