You didn't give any information regarding the original contract nor the nature of the business relationship. If this is his program, that you developed per his design and specifications, then 20% seems more than fair. I'd say in fact it's too high.

If this is your own program that he's just reselling on your behalf, then 20% doesn't seem fair at all.

Unfortunately, it's all the missing information that ends up being the most important in this case. If the situation is closer to the first example, then you really shouldn't be taking this thing on the road yourself. That would be a conflict and likely some sort of breach of contract.

The fact that you're asking this however leads me to believe that a well-defined contract doesn't exist at this point, nor did it exist when this program was started. That's likely the biggest mistake both of you made.

But what do I know... I'm just paying my contractors wage, salary and fixed figures. Only future permanent employees, partners and investors get a piece of the "action."

Bruno