Ideally, you don't want to go any higher than the knee block, true. Most goalies have torsional flexibility in the hips and knees enabling the skate boot to be parallel or near parallel to the ice when in their butterfly. I don't have that luxury anymore (don't know if I ever did, coming from old school goaltending in my younger days) and so I feel lots of stress in my ankles as my toes tend to want to point straight down to the ice, sometimes with an angle on a good day (thank goodness for the advent of bungee like toe ties).
I'm curious about the science involved as Maria's video was mentioned, and then you have makers without calf wedges, some with slight ones like my Warriors and then some with massive ones like the new Bauer Mach. It's hard to follow what is right and isn't. Other than Maria's take on it, I don't think there has been much written on the subject out there, at least available to the public.