Don't spread misinformation.
Yes, a longer ski DOES make sense if you're center mounting it.
Centermounting=less tip/more tail then you'd get for normal skiing. You need a certain amount of tip for your skis to react properly and turn well. Ever noticed how your center mounted 172s feel chattery and way too quick? Ya...NOT ENOUGH TIP YOU FUCKING IDIOT.
Then, take into account that most twintips are soft as shit, meaning that you can't rely on stiffness to give you the stability you need at a shorter length, and you start to realize the importance of length.
I can't back up skimasterflex's statement about the 185cm ARV being a better seller than the 175cm, but I can say this: We sold out of the 185cm LONG before we sold out of 175s.
That long-ish atomic jib ski makes PERFECT sense, and even more so when you start thinking that people will be riding that ski for big booters, park/urban rails, and even just general skiing.
I hope you don't work anywhere near a shop. If you do, I pity your customers.