Difference between "Passenger" endorsement & "School bus endorsement"- confused

In California you need a SPAB license, for hauling schoolkids.
They watch you do a thorough pretrip and posttrip, among other things. They will fail you instantly. On the backing they are very strict as well.
All this for the privilige of hauling little brats around who love to make your life miserable.
My previous company talked about making this SPAB a requirement for all the drivers. So many said they would quit immediately that the company backed off.

 

Here in Az the P & S endorsements are separate as well. Your passenger endorsement is strictly for hauling 16 passengers or more. I had my P endorsement to drive stretch limo's and limo buses. The S endorsement is needed for the actual school buses. However, the company I worked for being a private company would contract with schools for various school trips and we would haul kids to games or out of town events and most of us didn't have the S endorsement since it wasn't required. Most of the school districts here in Arizona are so hungry for bus drivers they will help a new driver get his Class B and the endorsements so they can put a driver in the seat.