The thing I think he's missing, and it's pretty obvious when the numbers are laid out like that is why were the Leafs giving up better shots with Hutch in net than with Fred in net? Despite popular sentiment, it appears that the Leafs were giving Freddy an average or better workload from a shot difficulty standpoint (something a bunch of us have argued for a while now). Why the spike with Hutch in net? I get that it's difficult to quantify but it's likely that the team just plays different in front of a goalie that can't stop a beach ball. You start trying to deny any shot attempts at all, and it creates gaps in the defence. That's the most likely explanation for why Hutch faced way fewer perimeter shots than Freddy, and more slot shots than Freddy.
When you're worried about 40 foot wristers beating him clean, you can't/won't collapse down to focus on taking about the higher percentage 15 footers.
I'm open to alternate theories on why the exact same defence gave up drastically different results depending on which goalie was in net, but the answer appears to be pretty obvious. Failure to recognize that underlying fact takes Berkshire's conclusions off track imo.