Sicotic,
Unfortunately, I wouldn't take anything you hear from anyone as far as rating/TDRL/PDRL/Severance too seriously. The PEB does whatever they want (within certain guidelines). I was diagnosed with Asthma, and rated at 60% by the VA. I have a rare condition where every medicine out there for asthma only makes my condition worse (if I took them all the time, I would be 100% rated all of the time). The PEB made the case that my asthma was not unfitting because I do not use an inhaler/other medication. Luckily, my attacks are not severe enough to kill me (yet). I went to FPEB, and they didn't care what I had to say or the evidence I brought with me. My lawyer said I would win for sure. Boy was he wrong! I wanted to appeal to SECAF, but my commander made it clear that he was going to start admin separation proceedings for my waist measurement and I didn't want to deal with that mess. So, I am now rated 80% from VA and 0% from USAF for a totally unrelated condition (well, 80% PROPOSED rating anyway - c'mon award letter!). I had one person I was supervisor for who couldn't walk because the Army jacked up her hips and she got a wonderful 10% and told to get out. She was 23 when she left military service and will be using a walker for the rest of her life. Of course, then again, I had another person who was found unfit for his back, PDRL'd at 60%, 100% Schedular P&T from VA (also had less mental problems than I have, he's PTSD, I'm not...but now I'm just griping). After 3 years of service he is raking in the money and benefits and I have seen him since he got out go playing volleyball and basketball for hours on end. I am not 100% sure how bad his back is, but I know my injuries wouldn't allow me to do that (much less my illnesses)!!
Bottom line, be prepared for anything! There is too much that can happen! From my experience (granted, it's limited), it seems like the VA at least tries to follow a set of guidelines that are decently spelled out. The PEB seems to have the power to do what they want...
That's my take on it. I hope I didn't scare you. The cases I mentioned were fairly extreme, and I have seen many, many others that were much more reasonable. I just wanted to illustrate that anything can happen when you are dealing with the PEB, so be prepared to either stay in, or get out and receive no benefits (that way you are prepared for whatever they rate you). I wish I had planned things like that, but hindsight is 20/20 and there is nothing I can do about it now.
Good luck to you and I hope everything works out the way you want.
Trevis