After forty-five (45) days the. Contractor may assess overdue account charges up to a maximum rate of one (1) percent per month on the outstanding balance."Down-payment" Minimum down payment of. (Joint Escrow Instructions). 1. Use our free payment plan agreement form to spell out all the terms and conditions of a loan if you need to establish a payment schedule with someone. If you need additional. A master purchase agreement is a legally binding contract between buyer and seller, and typically relates to buying and selling goods rather than services. Payment Processing Services. All State merchants are set up through the State's Master Service Agreement (MSA) with Wells Fargo Merchant Services. All payments hereunder shall be in.