Social Security Disability back pay will be paid in a single lump sum and will be reduced by the amount of SSI already paid for months when eligibility for the two programs overlap. The second SSI installment is due this month, but sometimes the installments are delayed.
The medium flat-rate boxes for Priority service are 13 5/8 inches by 11 7/8 inches by 3 3/8 inches and 11 inches by 8 1/2 inches by 5 1/2 inches. Shipping charges are $12.65. There is one small-size box offered for Priority service. It measures 8 5/8 inches by 5 3/8 inches by 1 5/8 inches and costs $5.95 to ship.
Size 16 envelopes qualify as flats as do the catalog envelope sizes 1Â¾, 3, 6, 8, 9Â¾, 10Â½, 12Â½, 13Â½, 14Â½, 15, 15Â½. The flats postage rate would cover international envelope size C4 but not C3. All items that are not letters, postcards or flats are considered parcels by the USPS.