License for 3d agricolture visualizer

If the visualizer is custom for one client, then your work-for-hire fees are royalty free. And since it won’t be sold at all or otherwise monetized, that will be royalty free too.

I’m going to create a 3d wineyard visualization system using unreal engine for which a company is going to pay me. The visualizer will operate on a data packet create using a 2D configurator. The company is not going to sell it: It will use it only for marketing purposes.

If I’ve well understood the license charge is for me on an amout of the 5% of the payment I’ll receive for the visualizer. Is that correct ?