Mike, I don’t understand

Mike,

I don’t understand what “x my hourly rate” means.Since you both agreed to the terms, I’d recommend you follow through with the first episode. You could then approach her, armed with your hard-earned data (hours spent, materials used, etc.) and inform her the price will increase for the following episodes and you’ll expect royalties…

So yes, it would be unprofessional to up the price of the first episode.