Don’t overthink it. Offer your $1800, so what if he doesn’t like it. What’s he going to do, block you? Oh my. You could wait some days, let him argue with some other folks first. After talking to various Nigerian Princes, guys sending a friend over with a check for the full amount, cat ladies wanting to trade a Turkish rug and a case of homemade jam, he may be receptive to your offer. Cash is always king.