Not even Charlie Eppes (of Numb3rs) can tell you the answer to your first question.
Regarding your second question, it has a very limited impact in determining who I choose to recruit. The star ranking of players is only based on how good the player is currently. It does not consider potential and therefore is basically useless in predicting future success. Also, in my opinion, the weighting system is skewed toward higher defensive skilled players which may or may not be relevant depending on which defensive scheme I am running. For example, it obviously would mean more in M2M than Zone. The only time it possibly has meaning to me is when I am looking at a position where I need someone to step in and get significant minutes right away. In that situation, the player with the better current ratings may be the better choice.