Why not?

If there are 160 passengers on board, only 10 of them check one bag each, but 8 of those 10 passengers is entitled to priority baggage handling, then 80% of the checked baggage (8 bags out of 10) will qualify for priority handling.

Obviously, that wouldn't have been the case on your specific flights given the numbers you cite. But whenever this issue comes up I am reminded of that QF study about the percentage of priority baggage on some QF routes, which AIUI led to QF basically terminating priority bags on those routes because it makes no sense to spend any money on it if 80% of the bags have priority.