Yes, could very well be. And I was wrong in my post way above - my BSL is actually 323.
No issues for me at a DIN of 10, but at 6'3" and 195 lbs, I can put some weight and leverage into the entry.
Haven't tried to put them on in bottomless powder yet, but yes, I imagine it could be a bitch. Of course, putting on bindings in bottomless powder is always a bitch.
Just thinking out loud, but I wonder if the Royal heelpiece might actually be an advantage in that situation? It's long enough that you could probably grab it to pull up and help lever the boot in? I've had to do that on other bindings, without much to grab onto. Just trying to see a silver lining here...