The store owner sold you a line of crap. You do not get extra distance from a superglide (ie looser) sabot.

The superglides came out because the regulars, black sabots, are very very tight in some guns. In fact, in both of my Omegas, I only tried loading them ONCE as the first one took a hammer to get it seated. The superglides are a little smaller and are the answer for the tight-bored guns.

My opinion that I am sure will get some agreement on here is that guns tend to shoot best with the tightest sabot you can comfortably load. In other words if you don't need the sueprglides, don't use them. If they are too loose, they will not be accurate both due to inconsistent pressure built upon ignition, wobble in the bore, or poor engagement of the rifling.

Some sabots have 2 petals, some have 4. Makes no difference, and neither does how many petals are torn off as the bullet is long gone when this happens. My Omega X7 shoots the 2-petal sabots on the 300gr bullets very very well.