Testing into compliance is a USP/FDA requirement for drug dissolution testing, the only test available and recommended to indicate the quality of the products in a particular tablet/capsule.
The reason for the 3- (or 4-) stage testing into compliance (USP/FDA Tolerance) is because of regulatory requirements of using flawed (also non-validated/non-GMP) dissolution testers and methods which are known to provide irrelevant and unpredictable results. Scientifically speaking, there is no reason to use the currently recommended testers, in particular USP Basket/Paddle, to evaluate the products. Blame the USP/FDA for requiring this testing into compliance practice, not the analysts and/or the companies.