How do you handle purchasing maintenance contracts through ePro?

We are using ePro and Purchasing 9.1 modules and use ePro to create all of our requisitions.

Right now if someone wants to purchase a maintenance contract we create an item in the database and have them select that on the requisition, which flows through the approval process, and is sourced into a purchase order. This is the same process we use for all other items, like laptops and monitors.

We are finding that the maintenance contracts are sometimes 3 year agreements, or require multiple payments over the course of a year so this is causing issues with matching and having purchase orders open for long periods of time.