In a computer-implemented method of conducting expressive payment reconciliation, a purchase transaction is stored in a computer storage accessible to a processor. The processor identifies a contract against which the purchase transaction is made and a first payment amount for the purchase transaction. Contract data is stored in the computer storage and the processor determines a second payment amount for the purchase transaction based on at least one good or service associated with the purchase transaction and the data about the contract. In response to a difference in the first and second payments, the processor either stores computer storage a modified invoice with a modified payment amount, stores in the computer storage a reconciliation payment equal to the payment difference; outputs over a computer network an explanation of the modified payment; or outputs over a computer network a dispute notification.