First two installments are 3 times the federal benefit rate ($733 in 2015) plus the state supplement in the state you are in. Final installment is the balance.
Makes no common sense. If SSI wants to be a Big Brother and save you from yourself by paying in installments, why would you be more capable a year later. But I have always had the cynical belief that it is a way that Congress can hold on to the SSI money longer so they can spend it elsewhere and pretend that there will be more money later, or that another Congress will figure out how to balance the budget.

