Do you ever let the seat creep more than once without correcting it? I know you have corrected enough that it would be way further back, but if you had just never corrected it, I wonder if it would continue to creep backwards.

For example, I have a motorized tv mount that is almost 10 years old and is no longer able to hold a precise position for more than a few days. I can set it and leave it hanging out from the wall, but after a few days it drifts to the left noticeably - but it just drifts those few inches and never any further. I can adjust it back to the original position using the remote and it stays for a few more days before drifting again - if I leave it after the drift it will stay in that position for months. I wonder if you're experience something similar with your driver seat (mechanical wear?).