
Theo, I think you're WAY over-thinking the OP's question.
He's not talking about how long it takes for the ball to travel from the Center's hands to the QB's hands.
He's talking about how long it takes for the QB to drop back AFTER he takes the snap.
He's thinking that since the QB usually likes to drop back to 5-6 yards behind the line of scrimmage before throwing a pass, that drop-back will take less time from the Shotgun formation than from other formations... in Shotgun, the QB is already 4 yards back and only has to drop back 2 more yards, while in other formations the QB is only 1 yard back and has to drop back 5 more yards. Since it takes less time to run 2 yards than 5 yards, he thinks it might help him.
I don't think it makes a difference either way, and I also think it's more important to pick plays that WORK in ANY formation, rather than clock-watching. It's all well and good to pick plays that you think will take less time, but you know what play takes less time than any other? An incomplete pass. And an incomplete pass is a waste of a down when you're trailing by 2 from your own 15 with 1:30 left and trying to get into FG range. You need YARDS. If you try to get cute with the clock instead of picking effective plays that move the ball, you'll just throw 4 incomplete passes and turn the ball over on downs with 1:10 left, and the other team will run the clock out on you.
If you're trying to time plays down to the second in your 4th-quarter offense, you're doing it wrong. It's just not possible in dotball.