My questions are simple but the answer(s) are elusive online,even on the official SSA site(s).
Background info you first need is as follows;
My wife gets both SSDI and SSI. I get SSDI. Our 2 children draw a check each off my SSDI called either Disability insurance or OASI.
On 1-1-2018 we all got the 2% increase or COLA, due to the cost of living increase of 2017. On the official SSA.gov site it states clearly that, the Maximum Federal Supplemental Security Income (SSI) payment amounts increase with the cost-of-living increases that apply to Social Security benefits. And: SSI amounts for 2018
The monthly maximum Federal amounts for 2018 are $750 for an eligible individual, $1,125 for an eligible individual with an eligible spouse.
I'm on SSDI not SSI, so does that limit pertain to me as an eligible spouse? Because I cannot get SSI at all,ever and there's no incom limit at all on SSDI.
Second question is: if the Max Fed payment amounts increase with the cost-of-living increases, can the SSA claim to legally take back the COLA under the pretense that they are using a "formula" to calculate how much SSI she can receive ?

Here's the case in a nutshell. 2 years ago they claim an over payment, we fought and lost and they deducted $ 23.70 monthly to pay back until paid in full. Then 10 months later claimed another "alleged" over payment of nearly double the first. We fought and won, and both over payments were dropped, she got back 3 months backpay times $ 23.70 but not one red cent of the original 15 months they took. We let it go for the time being. Nov 2017 she gets a letter saying she will get a 2% increase from $223 to $ 233 monthly due to the COLA . Now they say 2 months later that " due to an increase in income" she is getting dropped back to $ 223 monthly, which was the exact amount of the COLA granted by the Fed Gov't.
An appeal was immediately filed. She gets a missed call with a recording saying it's not the COLA they are taking back, but the formula used to calculate her benefit is what reduced her benefit amount, but they weren't taking away her 2% increase.
Do you see the circle here ?
I also cannot find the FAMILY MAXIMUM BENEFIT RATE allowed by law when all the family is getting some form of benefits. I can find tons of info on it but the calculations are vague and doesn't specifiy if it's based soley on her SSDI, her SSI, or my SSDI or her and my SSDI or the whole family''s income as a whole.
The SSA.gov site has done a tremendous job of hiding this info in double talk and contradictory rules and regulations. Please help us if at all possible and at your most earliest possible time due to this being time sensitive. We are taking the Appeal all the way to Federal court if need be and it looks like it will need to be.

Thank you for your time and patience in this matter.
Sincerely, DONALD

Hi Donald,

There is no unearned income limit (e.g. interest income, rental income, etc.) for people receiving Social Security disability benefits (SSDI), but there would be limits on how much you could earn and remain eligible for SSDI if you return to work. For more information, refer to this Social Security publication: https://www.ssa.gov/pubs/EN-05-10095.pdf.

Also, if your wife receives SSI (Supplemental Security Income) and you live together, then some of your income could be deemed as hers when determining how much SSI that she could be paid. SSI is needs based payment that supplements a person's other income. When the person's other income goes up, their SSI generally goes down. Assuming that all other variables remained the same, the recent COLA increase should have increased the combined amount of your wife's SSDI and SSI payments by 2%.

The family maximum benefit (FMB) refers to the maximum amount that can be paid to family members from a single individual's Social Security record. It isn't a set amount, but a variable amount that depends on the person's primary insurance amount (PIA). For people receiving SSDI, their full SSDI rate is the same as their PIA. Normally in the case of individuals receiving SSDI the FMB cannot exceed 150% of the individual's PIA (https://www.ssa.gov/OACT/COLA/dibfamilymax.html). In your case, though, since both you and your wife are eligible for SSDI it's likely that the FMB's on both of your records have been combined, permitting your children to receive higher monthly benefits.

Best, Jerry