I found it interesting today watching this match on TTC that during return of serve on prob 95 percent of the points the returning team played 2 back. In club level tennis you never hardly see the two players back on return of serve. I have played 90 percent singles for years and this year started moving into some doubles play. I've noticed that at almost every level of play anything besides one up one back will have a partner making faces at you. I believe to some extent players even up to 4.0 and 4.5, just stand where they see everyone else positioning.