E brake partially applied,shoes will cycle away from anchor pin,pulling cable and tightening adjuster. If parking brake is hanging up even a little, this will cause an issue. The backing up to adjust, as in slamming on brakes and coming to a stop is incorrect. With top of shoes seated against anchor pins you adjust shoes so you can get drums on/ off without force. Normal driving will adjust them.
Thats it. I dont have time to back up and stop 50 times.nor is it effective in the middle of winter.
I have done several hundred brake jobs, and never backed a single vehicle to adjust brakes.
If you expect a parking brake to hold, especially a hand brake, it likely wont. They just dont pull as hard as a foot operated parking brake.