Armstrong was riding for himself. Maybe that was part of an agreement: That AC and LA would ride their own races.
I think it was pretty clear on the first half of the climb that Armstrong was doing his best to limit time losses to AC. QUOTE]
Sorry not pretty clear to me,
You do realize Andy Schleck was up the road as well ? It is arguable that they were trying to reel him back in and would have sat on had they done so.
That also protects their positons on GC(Kloden & Armstrong) as well as gain time for the team GC.
So i say there are at least 3 compelling reasons for doing what they did vs your 1.