Ouch. This looks to me like the famous peddling of more expensive equipment. I have absolutely nothing against LM, their equipment or their prices, but this sounds to me like the guy was checking to see if you knew your stuff or not. He was hoping to make a good sale off of you. I can't believe any reputable shop operator with even a modicum of knowledge would recommend that kind of ball for a beginner.
There is nothing wrong with the balls you have in mind. A Tropical Storm, or maybe a Groove line ball would be fine. Just take your pick of any company's "entry level" offerings and you should be ok. Maybe let your son take a look at a few like a TS, Power Groove, maybe a Vibe, and pick one based on looks. Nothing wrong with that!
--------------------
Mr. Lebowski, this is Bill Salnicker with the Southern Cal Bowling League, and I just got a, an informal report, that a member of your team, uh, Walter Sobchak, drew a firearm during league play. If this is true of course, it contravenes a number of the league's by-laws, and article 27 of the league...