u/EnvironmentalPlan581

So my father went from 20 to 50 % which is amazing!!! I was told dfas had to do a audit then the v.a does their own in order for him to get backpay. dfas already did theirs . Submitted claims back in September got a decision in February. The letter states the effective date for his 50% is effective may 2025. Does the v.a not do backpay ? Did I understand something wrong? Some of his claims got denied and one got sent for higher level review does that stop v.a backpay?