True, but the real problem lies in that people can't just merge in the "zipper method". I think the point he meant to make was that if everyone properly used the "zipper" traffic would flow 35% faster.
This system of merging at the actual merge point is called the zipper: a way of intertwining traffic at one designated point. It only works if the drivers in the open lane allow cars from the closed lane to merge.
I guess it really doesn't matter WHERE you do it, but the idea is that traffic all flows along in two lanes, and at the same point, it all merges together. If that is when you first see the sign, or when the lane ends, it doesn't really matter. Since it doesn't really matter, the guys who close the lanes most likely put up the signs where the lane needs to close, no sooner or later. The key to making it work correctly is to have there be one point in the lane where everyone merges in "the zipper." The only logical place for that to happen is at the very end. Merging earlier just wastes road space, and you can't merge later.
The problem is that currently you have some people moving over as soon as they see the sign, then getting pissed at the people who use the whole lane and merge in at the end. The people who merge early wait in line unnecessarily and are all bitter about being so stupid, and then try not to let others merge. This breaks the zipper pattern.
The other problem is people stopping, or slowing down, in the open lane and waiting for a spot to merge. This is essentially caused by the people who merged earlier not letting them in. But it slows down the whole process, both lanes should be traveling the same speed to "zipper" properly.
Regardless, I will still be "that guy" and laugh at all the suckers waiting in the big line.