This is one way they cheat their claims when marketing higher amp alternators.
Chrysler test procedure shows how much current it can produce when held to 15 Volts or whatever the spec is for that alternator.
If it it didn't have to hold that voltage, but was allowed to hold 13 Volts, then it would putting out more amperage. But the max power it can generate at that rpm didn't change. So I guess thats a way to compare. Power = I * V.