Re coolant level, if that is the reading with your engine cold, and it never got low enough to reach the hose, then it has likely been okay.
Fluid and engine parts expands as they heat-up. So that pushes the coolant toward the higher "max" mark.
I looked at the reservoir in my '16 a couple of weeks ago and the hose is just below minimum. The reservoir sits higher than the radiator and engine so that should be a positive, but is it possible that air somehow gets introduced to the system if the fluid drops to hose-level; and that's what they're worried about?