Saying that they had "not demonstrated competence with revolvers" is, in my opinion, a VAST understatement!
Were I you, I'd pick up my guns and never darken their doorstep again.
IIRC (and if I'm mistaken someone please correct me) the method they're using to "show you" is used solely on Colt's revolvers to judge lock up and pawl ("hand" in S&W terminology) wear, and has ZERO to do with demonstrating proper carry-up (timing). This method shows you NOTHING on a Smith and Wesson other than that it's actually locking up and the cylinder stop is actually working. A touch of wiggle is dead normal, and as others have stated desirable. I'm unaware of an actual "spec" for the amount of wiggle. Perhaps someone more knowledgeable will come along with that info.
Wow! The fact someone would misrepresent their knowledge of a firearm to sell service on said firearm blows my mind!
I wish you well!