So does this mean a verbal acceptance is meaningless? Or are sellers not making decisions for days?
I would guess that this happens most often with small contracts that are priced below market, where multiple offers come in pretty much simultaneously. If the contract is priced below market, and isn't hundreds of points, several offers are going to be received in the first day. If the member who is selling holds a job, they might not be reachable for several hours, during which the reseller has gotten a few offers and the bidding war has started. At that point its in the realtor and the seller's best interest to hold out for a higher offer, calling the people who offered early and saying there is a higher offer on the table and giving them the chance to stay in or out.
Its why its important to know at what price you should get out. It isn't reasonable to expect a loaded OKW contract to get let go (and make it through ROFR) at less than $46 - knowing $63 was a deal and $64 too rich is the smart way to go about it. Its possible someone still got a deal on that contract at $68 - it would still be below market. Its also possible that it went for $74 and the seller got a deal.