I think ssa has not paid correct benefits to our children

My wife has been disabled with parkinson's since 1988.She was awared ss in 1989 for her disibility.At the time she was awared ss we had three children Jason 10 kimberly 3 and brittany 1 year old. My wife at the time reseived $395.00 and $45.00 total for our three children per month. I asked ssa if I was intitled to a benefit as father and caregiver of our minor children and disabled wife and the answer was no.As the years passed my wifes ss is at present $517.00 we only have one minor child and she gets $50.00 a month. I became disabled in 11/01/02 and was awared ss in 11/01/03 I get $746.00 a month and my two girls under 18 get only 47.00 a month since my ss started. One girl is turning 18 08/31/04 and now the 16 year old will get $50.00 a month.

My question is are we getting short changed.

Thank you for any help in this matter.