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If just starting out pull up your health records and see what conditions you can claim. What you want to do is claim every condition that you can. There are a lot of them and most Soldiers don't realize they are compensational conditions. Examples are Tinnitus, Female Sexual Arousal Disorder (FSAD) that most have. If you have any issues and have not been seen for them still claim them and make sure to see your PCM asap to report them and see if there is any treatment for them as well.
You don't get both VA and chapter 61 pension because by law any money received for your chapter 61 pension would have to be offset by any VA compensation you receive. So for most you just get VA pay and Tricare. If you are an officer and have a High DOD its sometimes possible to get more than VA because an officer's high 3 at a high DOD% such as 75% will be over the 4k that is often paid out by the VA.
Once you are medically retired you will want to look into CRSC. CRSC is there to help you recoup money lost due to the VA offset up to the amount your earned longevity pension is worth. At 10 years AD your pension is worth 20% for BRS or 25% for legacy of the average of your highest 36 months of base pay. So lets say your High 3 is 5k. Then if BRS 20% of that is 1k value of your pension. You are losing 1k due to the VA offset. If your qualified for CRSC at a % using VA tables equal to $1,000 or higher then you would get your $1,000 via a separate check from the VA. CRSC is tax advantaged too since its tax free. So in this scenario you would get 4k tax free from the VA and 1k tax free from DFAS for CRSC. I am just spit balling on the VA check of 4k. It can be slightly higher or lower for 100% VA depending on if married, dependent, Aid & Attendance, SMC's etc.
I always strongly recommend at the very least to interview private IDES attorneys. I will send you a direct message with references. My wife hired a private IDES attorney at the very start and she got an amazing results. There are so many things you can do to strengthen your case. Also, in your case its most likely that your referred condition will be TDRL which means even after getting out your financial future is not set. Even after out you will need to ensure to keep everything the same from taking meds to seeing a counselor until your condition is changed to PDRL. Getting out and immediately going to college or doing a full time job can show your symptoms are not as severe which means that 100% or 70% PTSD rating will be permanetly reduced to down to 10%, 30% or 50%. Below 30% means your retirement is revoked and all you get is a one time check and no more tricare insurance.