I'm having the same issue on the 10" i3v.

After every print, I have to either move the micro-stepping screw up or down (if i move it up for a print, I have to move it down for the next print, back up for the next, back down, etc.). I added the nut to the top side of the wooden z endstop mount, and I have a locknut at the bottom of the screw. Still have to adjust after every print.

Short of implenting all the auto bed leveling hardware, what can I do to alleviate this?