When I talked to the service tech, he told me the EXACT same thing about the ridge and the sensors.
I suppose I could get the rotors turned as well, but with the miles I've got on the originals, I probably should spring for a set of rotors on the next pad replacement shedule.
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car