WHO CARES ?
Buyers are allowed to pay whatever they want. They pay what they decide before we are called in to appraise. So we can't ask why they paid over MV, since MV is our opinion of the property, and they had no idea of that opinion when they negotiated price.
I was being a bit sarcastic when I wrote who cares...but the point is, we are not detectives engaged to find out why a buyer paid what they did. We are engaged to develop our opinion of market value. We can analyze a contract , but relevant as did contract contain atypical terms/terms affecting price. We are not lawyers and we are not forensic investigators into a past price negotiation we had no part in.
While it is informative for a client to know a reason why a buyer paid what they did, such as a concession, or a bidding war, or non AL terms etc, sometimes there is no clear reason. which is why in our comment, best is to reinforce why our OMV is supported, and that their CS price could simply reflect individual negotiation or market conditions.
The reason why these folks paid X and their motives for a CS price is really not that important , because whatever the motivations of an individual buyer, the appraisal opinion of MV derives from the assumed "sale" between the "buyer and seller" as typically motivated, at terms defined, in the MV definition. (of course we consider the CS price, to head off the accusation about ignoring it )