We can look to the post office to see that neutrality does not limit a provider to one tier of service.
The standard post office service will get my letter across the country to another major urban centre in a few days for the price of a first class stamp. If I want to speed things up I can pay for expedited delivery to get it there tomorrow. It's increased service for an increased price but those tiers of service are still neutral. Anyone can walk in and get the same expedited service for the same price.
For me the important thing about net neutrality is not that all data is equal, it's that data is transmitted in a uniform and non-discriminatory fashion. Hello Netflix, looking for enhanced video service? Here's the pricing chart. No, we won't block your competitors, and they'll be paying exactly the same price as you.