Basically yes.
The only amount the seller can charge for shipping is the amount he puts in the Shipping and Handling section. This is a separate tab.
If there is no amount in S&H he can pretty well charge what he wants to and you will be deemed to have agreed when he is bidding.
But.
If you don't pay the amount he wants , he is not going to ship. And eBay is not going to send a large man named Vinny to his house to make him ship.
They do have other incentives.
Report the listing. EBay will not tell you the result of their investigation.