Typically, all PT Sup's start at the same salary, if they are hired at the same time (starting salary of course may go up over time).
Additionally, annual raises are based on performance evaluations by their supervisors/managers, so also 'seniority' as a PT Sup can affect your pay, if you have had more opportunity for raises.
But, if you're asking whether there is a difference strictly based on work area, that answer is 'no.' They'll all make the same, other things being equal. There's no pay-bump just by moving areas of the building.
It would be far too complicated to do that way, as we have supervisors who will 'fill in' for other sups during vacations, personals, etc. or just to get trained in other areas...and that would be a nightmare for payroll if there were different rates for each area.
from what I understand they are all paid differently (hence the reason it seems to be nigh illegal to discuss what each other makes), but usually not differing greatly. Except in a case when say two hourlies go into it. If an hourly working at UPS 2 years goes into supervision they'll usually make more than one who worked there 6 months and decided to go into supervision. Least thats how it was explained to me.
Off the street hires, I have no idea how that works haha