the tricky thing is attributing causality to random noise. if normal noise is +/-1%, then yeah sure 4-6% is legit. but if you get 4-6% variation normally, then its kinda hard to tell if the recommender is doing anything or not. ofc, if it persists over an extended period, then that's cool.

im not saying this has no value, im saying people without a baseline (like me) have no idea how to assess this tagline and maybe there might be a better one to pursue.