With such a weak schedule, 10-6 should be the bare minimum acceptable for this team and that would be equivalent to 8-8 in most other seasons due to the schedule.
For the rebuilding to be considered "on schedule", the Bills would have to go 12-4 next season which is like 10-6 in most seasons.
Finally, to be "ahead of schedule" and "doing great", the Bills would need to win the Super Bowl.
Otherwise, you will know that Fitz sucks.