Or maybe it needs more credible liars on the sales staff? If the dude is coming up with stories no more believable than that one is about the cars he's selling, its small wonder the couple won't sign on the dotted line.
Even in the unlikely case that this is a true story, did sales boy ever stop to think that maybe the resulting sniggers and side ways glances from the rest of the sales staff the next day might have been a tad off-putting for the buyers?