Do these test score improvement "guarantees" by SAT prep courses really work?

Several of the online or virtual SAT prep courses offer 1400+ or 1500+ guarantees; others offer at least 150-160 point improvements. Any insights on whether these programs really work? Or are they just no risk gimmicks for them to offer?

My son’s scores improved a LOT. My daughter had exactly the same score. Because of that, she could have repeated the prep course at no cost. We weren’t interested.