Can they suddenly finish with a stage? Once they have worked through something can that behaviour disappear?
Hi Shantilly!
I can only answer based on what I witnessed in my H, but I believe it's true of many MLCers. I know we want them to hurry up already and zip through those stages, so we spend quite a bit of time analyzing how far they've got. However, I found it was only retrospectively, looking back, that I could tell when my H transitioned from one stage to another.
In my H's case, teenaged thinking (my H was 13-14 whereas yours is 16-17) was not so much a "stage" as an attitude. It fueled the emotionality of his Anger stage, the immature romance and obsession with sportscars and motorcycles of Replay, his "why me?" attitude during Depression, his choice of inappropriate confidants during Withdrawal, and he cycled between using his teenaged brain and his mature brain well into Acceptance. His C had to teach him how to recognize the difference between the two brains, and how to access and prioritize the mature brain.
The fact that your H is using his mature brain about the vehicle doesn't mean that he's finished with the teenaged one--teenagers, after all, can suddenly give up on one interest to pursue another--but is merely just a change in focus.
Watching your MLCer to see what stage he's in is about as much fun or use as watching the proverbial kettle boil. Plus, it's completely out of your control. What's in your control is your own life: what stage are you at in your quest to become the kind of woman you most admire? What would you still like to accomplish? Keep up the good work you've been doing.