chrisbl
Actually, no it isn't, because the cost allocation within BA is horribly skewed in all directions, and impossible to reconcile, since it's been built over 40 years or more. There have been attempts at various times to re-do it, they weren't completed for a variety of reasons.
I'm more than aware of the difficulty in doing this, that's why I talked of a principle and nothing more, in the case of BA those costs are far, far more complex than the short simplistic list you provide.