Continuity with Barney's hair sure does take a back seat in this scene!
(still trying to figure out whether Barn' uses Wildroot Cream-Oil or Vitalis as his hair slick... )
Wildroot and Vitalis were my favorites! Yeah, I gues the time crunch got them in this filming sequence.
I think the editors probably just gave up and decided to go with the flow on this one. "Runaway Barney" can't be stopped when he's rolling. And straining your brain to remember something like the Preamble can actually make your hair act in a peculiar way. (I read this in a Fact-A-Month Magazine.)
So, when Barney's brain was in a strain his hair fell forward in a limp, undisciplined fashion. When he was repeating something Andy had fed him from the hard copy his hair miraculously rebounded and looked like it was slicked down!
Miraculous the power of the human brain, isn't it?
Under a bucket or not, the human brain is an amazing thing!
I think it was more a matter of tight deadlines and never expecting the scrutiny we give. They probably thought the inconsistency wouldn't detract from the scene and it wasn't worth the time or budget to shoot again.
Obviously the scene wasn't filmed at the same time.