The Advance Curve Intelligent Envelope Processing System has an OCR camera that reads the address at speeds of up to 6,000 per hour. As the Advanced Curve reads the address it processes the address for CASS, MASS and does the address corrections. The Advanced Curve system calculates the zip plus 4 plus 2 and then sprays the IMB on the bottom of the envelope. This process qualifies the customer for the letter mixed AADC rate with out doing any sorting, that equates to a 5.8 cent per piece discount allowing the system to be cost justified with as little as 1775 letter per day. The system also qualifies for the Flat mixed AADC discount rate saving 15.5 cents per piece allowing the entire cost of the system to be justified with as little as 675 flats per day.