I think the only way you’d make your aids “accurate” is for you to program them yourself. I got close with the fitter from Costco (I have the KS9s - same aids as the 90s, with a couple features removed for 1/5 the cost) but it still wasn’t “accurate” to me. So I ordered a Noahlink Wireless, downloaded the target software and, sitting in front of my reference music system, as well as my acoustic instruments, and electric instruments, and tuned my aids for what SOUNDED “accurate” or pleasing to me. No frequencies jumping out, no frequencies in deficit, to the best of my ability. Real Ear Measurements show just what can take place on the way to the ear drum that can color the audio for the listener. Which is why I say, once we have a loss, the best any of us can hope for is to get aids that make us perceive that loss is mitigated by the instrument. The audiologist, the fitter, or anybody else, can’t really do it. And once that loss is there, the only reference we have is judgement from what we remember something should sound like.