Companies like "ach works" pull three days ahead. Issac is right, you cant rely on trust worthiness of a client to pay you off. The only thing you can really believe is submitted paperwork and that sometimes is doctored(thus the saturation of contracts with portals like decision logic and bank login information). The difference between the payoff balance and actual balance at time being honored, should be sent back to the merchant as stated. Otherwise merchants would being "paying off everyone," turning off their daily debit whenever requested, extending the term at their discretion. Good explanation Issac, with uncollateralized money, its pretty clear cut and dry. When the merchant has someone payoff the balance, ill turn it off. Any difference the merchant will see.