They're right you have nothing to lose, wait and he might just surprise you and pay. You will have the option to cancel after a number of days if he doesn't submit pymt. I do think it's too good to be true to have offered above asking for TWO domains, unless he wants them BOTH badly, AND you underpriced them. And you're right not to put too much weight on those Sedo yellow bars, however ime the opposite happened, it was slow earning them as a seller and the ones I had as a buyer (I had 5 at one point) disappeared altogether after some time when they saw I wasn't buying anymore, I think I have zero bars as a buyer right now. Sedo penalizes customers that way if they're not frequent buyers or sellers, and many bidders look at those ratings and judge sellers/buyers by them
And you SHOULD always send the domain to auction no matter how good the offer was, even this guy who made two offers above asking, always send to auction, who knows, in those 7 days (up to 7 days, if you think too long when you send it to auction there may only be 1 or 2 days left, auction time left starts running the moment the offer is sent, not the moment you send it to auction) someone may bid higher than the initial offer. Anyone who argues against sending a domain to auction or says it's not worth it waiting 7 more days would be nuts, it's all upside and NO downside (unless buyer tells you he's offering X if you don't send to auction, then you're kind of bound since Sedo has a record of that PM, although they probably won't prevent you from sending to auction just based on that.... but you'll look bad doing it..... or in a case where the buyer contacts you via webpage (if not parked w/Sedo) or the WhoIs telling you he'll offer X if you don't send to auction, you don't honor that and he may expose you)