They added only players who are just 1 point away from 6 stars so they can set a fair price. If there will be players like "fresh" 5 stars, their price should be 2,3 tokens and ofcourse they won't agree with that.

And yes if the basic price is 10 tokens, if you want to offer more, 1 token will go to seller and one will go to Nordeus, if the price will be 10 tokens and you want to add more the price is jumping from 2 to 2, 10-12-14 and so far.