Lease Compute Statements

We are just starting to look at using Lawson's Lease Management module in order to track leases with the new regulations. We're coming up with various scenarios to see how they would work in the new system. One that I'm curious how people are using is compute statements for payments. As an example, we have a lease that has a Year 1 base amount and then increases annually at a percentage of the CPI index increase.

I was looking at the computes, but we've really only used them with old report writer reports, so they're mostly just referencing columns in the report. Is there a way to get it to reference GL accounts (i.e. units to store CPI index) or prior period payments?

Or do people find it easier to just calculate manually and input in the recurring payment screen?

TIA