Knowing steam generally takes 30%, a minimum of 50% split would be acceptable to me. But at 25% I don't expect anyone to be going the paid route of steam.
Just to set the record straight, that data has no relevance whatsoever anymore, as Valve will not allow any game to directly sell workshop items. So how did it get there? It was entered as an experiment long time ago. I wasn't even aware that Valve had not removed all that information.