With the level 170 pair, I'd reset the things a bunch and get 3% stat lines all the time, never a 4% line.
Fed up with it still being rare, I drop an epic pot. scroll on it, it fails, weapons nuked.
After repotting the automatic replacement pair I'm getting 4% stat lines and never 3% lines.
I'm suspecting the lower item level tiers got carried up to the 170 set, but nuking them gave me a fresh start on pots for the 151+ tier or something.