How cooperative the system was being was completely unanticipated on Lex's behalf, and threw him for a loop. But the problem was, even though the system was being cooperative, Lex learned nothing new.
So not only would Lex have to pay some kind of penalty for his questions, he was getting no real answers either. The only assurance he had that the system was not out to harm him was its word. For now, he would live with that.
What was most important to him, however, was to make sure that the system did not fuse with his soul, and that he got some say in how the Inn operated from now on.
He was adamant on rejecting the fusion, for his soul was literally him. If an unfathomably strong system, which also had a soul of its own, fused and became a part of him, Lex would have no idea if he would still be Lex moving forward, or he would be the system. Or perhaps, he'd be something entirely new altogether.