Part of him wants to optimize the part where, apparently, whatever devil signs this contract just gets all that money, but eh.  It's just 500,000gp at some point into the far future of their relationship.

"Well, think no less of me if I don't sign your very romantic contract upon the spot.  I do need to check the terms.  I don't suppose you asked the devil about unexpected unpleasantness?  Should've actually asked that explicitly."

Part of him wants to optimize the part where, apparently, whatever devil signs this contract just gets all that money, but eh.  It's just 500,000gp at some point into the far future of their relationship.

"Well, think no less of me if I don't sign your very romantic contract upon the spot.  I do need to check the terms.  I don't suppose you asked the devil about unexpected unpleasantness?  Should've actually asked explicitly for you to do that."