My experiences tell me that Hertz usually treat airport locations and nearby (<10 miles maybe?) locations as the same for drop-off. Some examples:
1. When making reservations (pick up from both airport and HLE), the quoted rates were always the same whether I pick PIT or an HLE as drop-off location.
2. Reserved HLE-1 pick-up / HLE-2 drop-off. The contract indicates the drop-off location as PIT. Drop-off HLE (HLE-2) says nothing and I was charged the quoted rate.