For some definition of "normal circumstances". Being a bigger user should fall within it or that's not accurate advertising.
Some places will offer a choice between faster metered and slower unmetered. That seems like a good compromise to me. A nice big link should cost the host a single digit number of dollars per 100Mbps, so it's not hard to find an option where everyone is happy with the speed and pricing.
If you want a contract that has every term and circumstance negotiated up front, you’re going to need to speak with Hetzner’s business development team. You’ll also need to be a bigger fish than a single hobby developer.
Some places will offer a choice between faster metered and slower unmetered. That seems like a good compromise to me. A nice big link should cost the host a single digit number of dollars per 100Mbps, so it's not hard to find an option where everyone is happy with the speed and pricing.