In the nature of TMA, as I see it, there is the "intention" to not only come back to the green line, but in addition come back to the other side of the channel
(no problem for english, between strangers we use simple words and we can understand each other often easier than with native speakers )
yes i understand your point of view ( i like bollinger
) but unfortunately it can't be enough simple i think 
because when you will be in a nice trend you will lose several consecutives trades,
furthermore you know that boxes deliver a lot of signals especially when the market becomes choppy so you must be careful
Having everything you say and what I've just write in mind, maybe the TP line depends on the psycology of the trader...
yes psychology but more important , in which perspective are you ?
scalp,swing, with/against the trend,reintegration,range, etc etc
so if you want to let run the movement you need to be sure the previous movement is terminated and so need others indi or analysis of other TF,
try to catch big swings against a trend which is not yet dead is a non sens in my opinion
are you looking at my pc??? I have been playing a couple of days with the same indicator!!!!!
)