As others have said at CDG bag drop is an hour other places due to distances or extra time in security or a notorious immigration so the eye roll saved your entire trip as you could have had fare difference plus change fee or new ticket..
Immigration at CDG can be a zoo so you were lucky though with 5 mins before the official gate closure.
I’ve noticed MMB not as accurate as it was eg use Galleries First when Travelling F but it does usually have opening and closing times of bag drops and check in desks.
Happy travels.