I see. Welcome to the thread!
Unfortunately we do oftentimes communicate in our own language as there are some points that can easily be made understandable when using the basic tongue.
Now for your question. There is no difference with CEM and with other VOs in doing the security/criminality checks - all are the same. Where the timelines get extended is often with security screening - to which we applicants have no input as this is done internal with Canadian agencies (presumably) querying security agencies of the other countries; it has been observed that the greater number of countries resided will add in to application processing - possibly due to the number of security inquiries needed and the added waiting time for the response to each. The indication of "In process" often shows that admissibility checks have started or in progress; let's assume this includes the security checks as all these admissibility checks are done in parallel. But the response to these queries may not come all at the same time; some may take a longer time than others. The PCCs are only one input to the security/criminality checks.
I see from your timeline that tha last update happened 6/19, after you had sent in the additional documents and updated personal history, and that update (medical results received) is 3 months after completing medicals. I will surmise that update is not because of the medical results were actually received or even completed (IMHO - 3 months is too long to forward medical results and complete a medical assessment...) but because there has been completion on some of the pending admissibility checks (but not all). Perhaps pending is a response to a check based on your updated personal history or a pending is completion of a security assessment to reconcile the information in the updated personal history with what has been received.
Nevertheless, there should be movement in your application in the coming weeks and barring any other requests a PPR should be due soon. Your processing did indeed ramp up after the transfer (lots have happened in the 4months), that is one very welcome development.
.../hth and atb