Looking at that website seems like a joke. I checked out the employment page and they don't ask about any certification levels. It seems to look more at ability and years spent riding.
I'm an NZ Level 3 and currently working in Utah and completely understand your thoughts on unhelpful advice or lessons from instructors. A lot of instructors here aren't even certified and it drives me insane. If you're getting an advanced lesson then chances are you're going to get a qualified and experience coach though, as they won't, or at least shouldn't be putting unqualified or low certified instructors on those groups.
That being said, if you get a private lesson, then you never know who will be teaching you.
Most private company's operating such business have permits to teach at those resorts, and if they don't they will get stung pretty heavily when they get found out.
A good way could be to ask about the instructors qualifications and experience when booking a lesson. In groups this is usually not possible, but when booking a private it may be possible depending on the resort.
Another option is to find the instructors during their line up at the start of the day and talk to them personally to find one you trust and get a lesson with them.