if you follow the story line in the text it does make sense to have to different outcomes and depending on if she tries with her feet under the table during dinner or not.Correct indeed sir. Which makes no f**king sense.
The BJ is a consequence of Lily making her self look cheap (they end up in the sofa to talk business). Luke looks down on her because of her behavior and thinks she will do anything for the deal and thinks Markus told her to do a BJ on him, therefor the BJ.
The other path she plays the perfect business woman. He is looking for a life partner/girl friend and he is so impressed, finds her so attractive and feels connected to her that he wants to make love to her (not just fuck her to get off - there is a difference), not because of the deal but because he is looking for the perfect woman for life...
So it does make sense if you follow the story lines