A fixed fee needs a trigger
Fixed does not always mean paid at signing. The trigger may be delivery, validation or acceptance. Break the amount into guaranteed and conditional milestones, and ask what happens if acceptance is delayed.
Revenue share needs a definition
Ask whether the percentage applies to gross receipts, net receipts or another base. Identify deductions, related-party transactions, bundled deals, reporting frequency and audit rights. A high percentage of an uncertain base is hard to value.
Hybrid structures need two reviews
An advance plus future share can combine early cash with later upside, but the advance may be recoupable. Check whether it reduces future payments, whether there is a minimum guarantee, and how termination affects future sales.
Model scenarios rather than forecasts
Use zero, low and higher resale scenarios to understand sensitivity. Do not call any scenario expected income without evidence. Consider how long you can wait, how much reporting you can administer and whether the license blocks other opportunities.