one more clue, perhaps, is that the while which 2 lines autoscroll seems to depend on where I wrote last (the 2 lines I didn't write last are the ones that scroll), the autoscroll commands are always sent first to the upper 2 lines then to the lower 2 lines.
I think I am finished with the project at this point, unless some smart person can figure out that last bug. I've done a lot more than I set out to do at the beginning, which was just to get it working with the 40x4 display. I've learned a lot and had a lot of fun doing it.