Seller finance payoff agreement

[Tim Heizer]

I purchased a property a few months ago and the seller agreed to finance the deal at 0% over 30 years. In fact my first payment isn’t even due until 12/1/20.

My original plan was to sell it via lease purchase and pocket the cash flow. However I got a really great cash offer so I called my original seller and he agreed to take $20k less if we can pay him off within 60 days. 

My question is when I accept the offer and escrow is opened at the title company, what should I do do make sure the payoff amount at close is the verbally agreed $20k less? The mortgage note for the seller financed deal was recorded for $150k. Should I have my seller sign a statement saying he will accept $130k as payment in full if paid by 12/31/2020? Will that suffice as a payoff statement for the title co?

suggestions?