I like it! Make sure they know it is a "ONE TIME OFFER!" or they might think you'll do it all of the time.
We have water billing that needs to be collected. I think I'll use your idea, except I'm going to only offer it for 30 and 60 days. Maybe 15 and 30 days? Great thinking!
Our company doesn't offer a discounted rate based on payment time.... but if the vacating resident signs and KEEPS a payment agreement with the leasing office, it doesn't get turned over to collection. Keeping it off their credit report is a huge incentive for the resident, and we don't have to split cost with the collection agency. There's no leniency, though - miss a payment or are late, and it immediately gets sent to the agency.
This is a good idea. But I feel that 90 days is too much. How about you try 30 and 45? Because you don't want balances going into second or third month. Or are you making this offer because you don't feel that the previous tenants are going to pay up at all and this might induce them to pay?
If you make this a one time offer as sandy suggests then it might be a good idea for 30,60 and 90 progression.