It seems that when you start last in your class, you start 1st in the class after that. For example:
A CLASS:
MadMax
Snoopy
[LSD]Jalicno
[LSD]Love
Pyrofox
B CLASS:
Killerbunnies
Gen
[LSD]F4lc0N
In this case, Pyrofox is last in A CLASS. But instead of starting last in A CLASS, he starts 1st in B CLASS and everyone else in B CLASS is pushed back one grid space.