Breaking Serve Happens More In The Ad Court
Returning in the Ad court is intrinsically more important than it is in the Deuce court, because this is where over 75% of the break points are played. The Ad court is where more of the big points live in our sport, and interestingly where more returns come back in play.
In a lot of ways, there is very little difference returning in the Deuce court and the Ad court. But there are definitely differences.
Maybe the Deuce court is a place to attack more, which means you also miss more. Maybe the Ad court is a place to make balls and neutralize serves with consistency. Every match can be a little bit different, so I don't think there is any set formula for exactly why.