I don't dispute your claim (and am personally swayed of the argument of technical > admin in most situations) - do you have data that shows this disparity?
Purely conjecture (which means absolutely nothing), I've always assumed that admin:faculty rates are similar, but the volume is where it matters (ie. 2x more admin:faculty in headcount).
I don't, but suppose on a pure hourly basis they're paid the same. I think that's still unfair, given the amount of value a CS lecturer delivers over an admin.
Purely conjecture (which means absolutely nothing), I've always assumed that admin:faculty rates are similar, but the volume is where it matters (ie. 2x more admin:faculty in headcount).