Hi absolute
It is definitely before medicals as this is when you get the medicals, viz all selection and eligibility criteria checked etc etc. which includes the intention to settle outside Quebec. Unless the officer is not satisfied, he will not put in the selection met note for the system to generate the medical request. They instead send the email to prove or demonstrate the intention to settle outside of Quebec.
This could happen anytime i.e. year of application. 2012 applicants are much delayed but 2013 are running like bushfire (happy for them). It is not done by SL but final selection by FA. My file was first examined by CPP in March and POF request generated. No questions about Quebec residency then. I have been providing them with documents proactively such as offer letter, thesis submission, thesis defence, joining letter etc.
Whenever they open your file for final assessment is when you get the explanation email, so no clear answers as no one knows, so track the tracker, pretty much its predictable except few jump the lines. So you have a rough idea of anticipation based on previous months.