Am I understanding this correctly,

Vader takes an action, then takes another action, then uses PTL to take another action gaining a stress token Then next turn I can green bank move him to remove the stress token?

So for example Target Lock, Focus, Barrel Roll?

Yes

It works but taking that Stress does increase the chances that something happens which will keep you from getting rid of it easily which will kill all your actions.

Don't get greedy with Vader. Two actions is more than enough. He's immensely fun to fly without PTL.