Okay, here's the deal. If you were 0% rated from such and such date to such and such date (my medical ETS in '04 garnered me a 0% rating, that I could have appealed, but was made fully aware it could take two years --during which time I'd have ETS'd nomrally. So I opted not to appeal it. VA got me rated 30, 60, 75 and now I'm finally rated 100% and unable to work. I also got SSDI, and by all accounts, I was approved extremely fast and on the first application --just a few months passed.
So out of the blue 9 months ago I get a letter from DOD saying they screwed up the medical board and that everyone was basically given 0% the first time! So they got caught, and now they are reviewing your ETS board file in addition to any medical evidence you can submit (from VA or civilian doctors) --in essence, they are now considering not just the military medical records, but everything from then until now, which can likely give you a significant increase in your military rating.
However, you won't be getting additional pay. Pay is capped to whoever pays the highest I think, so if VA pays you more than military will, you'll only get the VA check if I'm reading it right. If you haven't gotten this letter, you need to look into it.
I've been round and round with VA, it's a full time job if you're damaged enough. Folks with good things to say about VA likely haven't been admitted or had to go through the byzantine system for more indepth healthcare (which is dubious to say the least).
As for them dinging your insurance, I tell them I have no insurance outside the VA. And I really don't, just SSDI. I do use a civilian pain doc, as the VA just totally screwed that all up. They're one horror story after another.
They mention you getting checked out by a doctor outside the VA, a third party, in order to "speed things up" to usher along your claim. These guys are half assed and I'll never go back to one again. You DO have the right to request an in-house VA doctor to look you over. You don't HAVE to go to the one they try to send you to.
If you haven't, you need to get set up with American Legion (who I use) or some other advocacy group. They know how to navigate the VA and get shit done when you can't. See, if you miss one of these comp and pen. exams, they only use whatever they have to come to a decision. You'll need to contest their decision to send you to a third party and it works best when using a liaison like the Legion, etc. They usually go out of their way to help you.
Good luck, and if you have any other questions or specific questions and I can help, PM me and I'll do my best. But my best advice now is to get aligned with an advocacy group and get ahold of one of those letters that allow you contest the military's findings. File increases in your claim, if you're service connected disabilities do in fact get worse and affect quality of life, you are entitled to compensation. You earned it, it was part of the dotted line.