Three-year contracts: do you credit total contract value or the first year only?

Facilities management software vendor in Vancouver, 55 account executives selling to property owners across Canada. Until recently nearly all deals were one-year terms. Finance has started offering a discount for three-year commitments and about a quarter of new deals now sign on that basis.

Our plan credits annual contract value, so a three-year deal earns the rep the same as a one-year deal at a lower price. Unsurprisingly, the reps are not offering the longer term unless the customer asks.

Do you credit multi-year deals at full contract value, at first-year value with a multiplier, or some other way? And does it matter whether the customer pays up front?