Hope this thread doesn't deteriorate any more than it already has.
Anyway, in playing dubs I normally play at net. Positioning varies to give the opponents different looks along with a few fakes here and there. I watch a lot of Bryan brothers matches and tips.
The only time I move back near but not completely at the baseline is when the returner is really strong and hits the balls way too fast for me to intercept. Once he returns the ball, I sprint up and try to take charge of the net again. Sorry, old school habits I guess.
Cindy, it's probably best for you to simply ask your partner. That would get you the real answer why he changed his strategy as opposed to posting here and getting a barrage of suggestions based on assumptions only from your side of the story.
r,
eagle