I had a hunch...
Let me be honest, more times than not when someone tries to improve these kinds of surfaces they end up making them worse and then they're unhappy and looking for someone to complain to or replace the component.
At Meguiar's I would send them to Tom McDonald who at the time was in charge of taking care of really hard problems, he's since moved onto a different position but I know I never wanted his job.
Usually a person, (you in this case), has very high expectations, that is after rub any product on the surface and wipe it off you expect perfection and most of the time that's not what you get and part of the problem is the surface you're working on is very scratch-sensitive. Having it right in front of your eyes doesn't help either as you're going to see it every time you get into the car.
PlastX is a great plastic polish but usually still wouldn't leave a PERFECT finish for surfaces like this when applied by hand. Part of the problem wasn't the product but the pressure exerted by your fingers on some kind of applicator material like a foam applicator pad.
I haven't had time to try all the other plastic products on the market but again, from years of experience watching and helping someone in a thread like this getting perfection is pretty hard.
What do you have in your detailing arsenal as far as chemicals go?