I know it's been debated ad nauseum - but recurring royalties based upon per unit usage of IP in the classical sense of the term is open to a lot of interpretation and foot-dragging. Signing these companies up for distinct dollar amounts whether it be in one lump sum or spread out over multiple payments (and hopefully larger and larger dollar amounts-Ha!) may be the better way to go even though "Recurring Royalties" seems sexier. JMO