It's been my experience that new offenses tend to be more effective earlier in the year than later. It's a common misconception that offenses have kinks to work out, when in fact they often come out of the gate strong and catch teams off guard because there isn't a lot of film on what they're doing. It's harder to prepare for a team that is doing something differently for the first time, as oppose to facing a coordinator that has been running the same offense for years.
We saw it in our own offenses early on in Charlie's tenure, but you see it happen every season in other teams. Early in Weis' career we came out of the gate pretty strong, but as we got to November the Pitts and USCs had some success slowing us down. The exception was in 2007 when the offense was just starting to come together at the end of the season, but that whole year was a bit of an abortion because of the lack of leadership and upperclassmen left behind from Ty's final recruiting classes. Overall though, Charle's tenure and his offenses were less potent by the end because they were old hat.
I'm not saying that a team running a new offense is going to be running on all cylinders day 1, but generally among bigger programs I've seen teams have more success than failures (At least early in the season) when they're switching to a new system. Smaller programs may have some growing pains if they don't have the personnel to make a switch right away, but you get the idea.