It's also possible that the Engine is, and was, offered under multiple terms simultaneously to hit different parts of the market.

I'm speculating (yay internet!), but for Enterprise components developers profit from there's often a "buy the cow up front" option along with a "free cow today for a sip of the milk tomorrow" model.

Star Citizen, particularly before the crowd funding, wouldn't have wanted to give them a lot of cash up front, and got some really nice concessions in the deal (free promos and development).