I think the timeouts are scheduled for the same time, but they just make them longer.
A lot longer.
They do the same thing in the NCAA basketball tournament. Former UCLA coach Steve Lavin said you could play fewer players in the NCAA tournament because the timeouts were so long that you could get players longer rests.
I can’t find an online reference to back me up, but I believe each team gets a seventh full timeout during the Finals. The only thing I could find to check on that was the ESPN game-log thing from Game 2, and it had the timeouts listed as number 1/7, 2/7, etc, so I think that may be the case. Like I said, though, I don’t know for sure.
I looked at the play-by-plays on the NBA website for the first two games and in Game 2, the Lakers, who used up all their timeouts in regulation, took six full timeouts and 2 20-second timeouts.