My wife (age 62) is on SS, and our disabled adult son has just been approved for DAC/CDB benefits. I (age 65) will be filing a restricted application for Child-in-Care benefits and not applying for SS on my earnings history until age 70. I have used the SSA formula for calculating Family Benefit Maximum and am trying to determine how my CIC benefit will affect my son's benefit. Is this the correct formula to use: ( [Family Benefit Max] minus [my wife's benefit] ) divided by [# of auxiliary benefits which is two in this case for my disabled son's benefit and my CIC benefit]? Also, would I use the current amount my wife is receiving or her FRA PIA benefit amount in the calculation?

Hi. You need to subtract your wife's primary insurance amount (PIA), not her reduced benefit rate, from the family maximum benefit (FMB) amount. You and your son would then split the remainder.

Best, Jerry