Team Power Rankings are like WAR in this game; too complicated and subject to change for the developers to actually define publicly. For example, this is literally all that the online manual has on the subject:
However, fifteen years ago, GMO * set forth a formula that no one has ever topped or denied since to my knowledge:
A formula to calculate power ranking points
If nothing else, that will give you at least an idea of how Team Power Rankings are calculated. The ++, +, o, -, and -- refer to how far you are rising/dropping compared to last week's ranking. ++ means you improved a lot,
that sort of thing.
* I like his sense of humor in the OP.
