Yes it should change to we are reviewing the additional documents, but that will change when officer looks into file.On my end, it says "We have received the additional documents you provided.".
I have checked with few more applicants who received passport request and for them it changed from received to reviewing at some point.
I am also waiting for DM and than passport request. Mississauga is very slow from last few days.
I hope the officer looks into it soon. It is so much of a dilemma as what to do. Booking the flight and then cancelling later is a waste.