I think he should have sent the starters to the bench the whole fourth. The second unit was doing fine and it was they who had us up by 20. KG and those guys actually let it slip to 16-18 points as I recall.
The lead peaked at 25 with Jermaine and Ray out there with Bass, Dooling, and Marquis. It was at that point that Doc put in Stiemsma and Sasha for a full 5 man bench unit. This was with 1:36 left in the third quarter.
It was back down to 18 when KG/Ray re-entered the game with 7:48 left in the fourth. The full 5 man bench unit had lost 7 points in about 5 minutes, so no they really weren't maintaining the lead all that well, though it wasn't a disaster.
The other thing to consider is that this team is still developing its rotations, you don't want to necessarily over extend bench guys just yet. Besides no one played over 29 minutes so the starters weren't run into the ground.
I'd expect less than 29 on many nights for Jermaine honestly, but he had it going and had been limited by fouls the last three games. It was good to get him extended run where he was a factor.