I have legal custody of my twin granddaughters, age 10. They have been with me for eight years. I'm 73 and retired and drawing SS of ~$2,600/mo. My wife is also retired and receives 1/2 of my SS. I expect to be awarded adoption in Colorado sometime late this month or early next. SS told me that I can get 75% of my SS. That would work out to around an additional $2,000/mo. Is this accurate?
Well, it doesn't sound like you got the full story. As long as you're living, the most that an eligible child could be paid from your record is 50% of your primary insurance amount (PIA). A person's PIA is equal to the amount of their Social Security retirement benefit if they start drawing at full retirement age (FRA).
However, there is a family maximum benefit (FMB) that can be paid on any worker's record, and if more than one family member is eligible for auxiliary (e.g. child, spouse) benefits then their individual benefit rates can be reduced due to the FMB. If your PIA is more than around $2300 your FMB would be roughly 175% of your PIA, meaning that up to 75% of your PIA would be available to be paid to eligible family members. In other words, the total benefit rate that could be paid to your family members would likely amount to 75% of your PIA, but that includes your wife's spousal benefit.
For example, say Bob has a PIA of $2400 and is drawing his benefits. Bob's wife is FRA and is only eligible for spousal benefits. Bob has 2 minor children who qualify for child benefits on his record. The FMB on Bob's record is $4200, or 175% of his PIA. After subtracting Bob's PIA from the FMB, that leaves $1800 that can be paid to eligible family members. Individually, Bob's wife and children could each qualify for up to 50% of his PIA, or $1200, but they can't be paid that much because of the FMB. Instead, Bob's wife and children must split the $1800 available due to the FMB, resulting in them getting a monthly rate of $600 each.