Welcome to B&B nice little set up
I guess maybe like the previous poster a new head design? They seem to change model numbers with every head or handle design, so it happens quite often sometimes.
What are the blades you're using? I've gone over bumps and such but maybe I wasn't using blades as sharp as yours since I haven't really sliced much at all except while trying to go XTG on my upper lip and that is just difficult!
But yeah, the members can give pretty good recommendations on blades, let us know your whole set up!