The installment process for retroactive SSI checks was mandated by Congress. It started as a Big Brother method of making sure that SSI receipients don't do stupid things with large sums of money because a few people did that after a court case in the 1990's called Zebley. The first installment process was palatable. This new process of paying 3 months of SSI at first, 3 months of SSI six months later and the bulk 12 months later is ridiculous yet it is the law. Your local office cannot thumb their nose at the regulations just because they don't like it. IMO, it is an attempt by Congress to hold on to money longer so they can spend more of it somewhere else. This is a provision that started in the Clinton administration, was tweaked in the Bush administration and has been left in place by the Obama adminstration. Only Congress can change it.

There are exceptions to installments for SSI. Read the award letter. Bring evidence to your local office that you meet one of the listed installments.

Also, because you have an SSI claim, if the SSI claim is paid, the retroactive SSDI will be offset by the amount of SSI that would not have been paid if the SSDI had been paid on time. Read that sentence a few times. It is called windfall offset and often slows down the processing of retroactive benefits.

The ALJ only writes a decision. The payment center staff does not start on paying your claim until after a favorable decision is written. Then, if all the non-medical documents have not been submitted previously, the payment center has to contact you for more info. The local office effectuates payment on the SSI claim after you provide proof of all income and resources (non-medical info) and living arrangements since you filed a claim. Once all those non-medical issues are resolved, payment can be made.