Dude, you have a source on this? No offense, but it sounds like horrible advice. Taking practice tests improves your pacing and endurance, and helps to prepare you for the test day experience. But, c'mon, if you do it your way, you're just going to keep making the same mistakes again and again. Yeah, I guess you'll figure out what they are during the "last stage of your preperation," but by then it might be too late to fix them.
There are lots of people who get stratospheric scores and only take something like 20 prep tests.
Quality over quantity, dude.