DarSum:It's back to speeding up when it passes the hook line.
That is what I hate more than anything with this game, sometimes it seems like the damn meter is actively trying to annoy you, it creeps slowly slowly and just before ding line it sets of like a rabbit on crack. If you try to compensate and hit early, you end up clicking before it has started to accelerate and find the trees to the left.
It seems that the slower the meter, the more it accelerates.