Having been seen at 6 VA hospitals and several specialty clinics for rehab etc, here is what I learned. Timing is everything, go in and be different than everyone else, the angry vet with all sorts of military crap on they see every day. I go in dressed nice, act nice, am super polite and they fall all over me. Granted I did file a complaint on a contract doctor that tried to send me home after I waited two hours past my appointment time, but they quickly canned that clown.
When I left the service, I was on crutches and they rated me at 30%, years later a VA doctor asked me the rating and I told him, he told me he had never seen a record that thick at such a low rating and to reapply, I did, and he was right it was too low.
Somewhere near you is a VSO, usually at a VFW or AMVET, they can help you with claims. Don't even try it alone, the process is crazy. The worst you could do would be stay at your current rating, but you could get hearing aids and more, I am always encouraging local vets, especially the older ones to reapply, the VA has gotten way better.