It sounds like your wife is being penalized for not going on medicare when first eligible, which would have been 2 years after going on disability.
It happened to my step father, who is a disabled Korean War vet. He used the V.A. until he was 80 years old, then switched to medicare and his premium is $200, because he didn’t sign up for medicare when first becoming eligible. Normal medicare premiums are around $100.
That’s what I think too. She was originally under my Blue Cross Blue Shield when she first went on disability and then when I went to a new company they said she could apply for Medicare in 17 months.