So many ways to calculate GPA...

<p>I've calculated my GPA a few different ways now, but which way will colleges calculate it(specifically Penn)?
My school has a system out of 100, in which they just average all of my grades together and that's my GPA. But most other schools use a 4.0 system (I think). Will Penn go and actually recalculate my GPA on the 4.0 scale?
According to my counselor, an A gets a 4, B a 3, C a 2 and so on. But then how is it that people have weighted GPA's over a 4, can you ever get over an A?
Also, how many points get added to your grade in an AP class- if you need to figure out your weighted GPA? My school adds 8 for AP, and 5 for honors, now is that serious grade inflation, or just the norm?
Im pretty confused (luckily im only a junior), so I can use all the help I can get. :)</p>