Re \"Unalterables\"-- A par, by definition, is an average. An average, by definition, means the underlying data has NOT been constant. Using an average and calling it a constant doesn\'t make it one, and doesn\'t have any relevance to a specific case, but it sure makes it easy to come up with a figure.

I remember it well.

NoCarolinaTony: Now Jerry if you start talking standard deviations and  six sigma......I will know the whole world has gone upside down....

NCT

TGJB: Fortunately, you don\'t need to know that stuff to make figures.

You do, however, have to have a little common sense. But only if you want to get them right. If you want to SOUND like they are right, you use the word \"objective\" a lot when it has absolutely nothing to do with what you are talking about.