I personally wouldn't read too much into that timeline, it differs for everyone. True, they have to provide estimates to people so they have a rough idea of how long they'll have to wait, but they are exactly that, rough estimates!
My medical request said that I should expect to hear something within 120 days, so I'm not going to bother with GMC notes or whatever until after the 120 days. Thinks seem to be moving along quite fast anyway, so those estimates are probably out of date anyway!
Sit tight folks, PR is on its way!