Achieving Mastery awards on Xbox has always been difficult, due to the "stealth sign out" of Dovetail Live, a well-known issue. However, Harlem Line takes this up a notch. I like to save near the end of a service, because the service completions don't always count towards the award (broken). I just keep running the very end until it counts. this time, I actually had a scenario completion taken away, so I went from 3 completions back down to 2! The M7A mileage requirement is even worse. More often than not, my total miles has actually decreased after completing a service. So now I only have 17 miles towards the 80 required, even though I just got the achievement for driving the M7 122 miles. Sheesh.