Why do credit requirements differ depending on the Asset Plan?

Hello @Titanuim, the cost of assets in Adobe Stock is calculated based on the plan's price, and as @Abambo mentioned already, the extended license is cheaper if you have 750-asset plan compared to the 10-asset plan.

It's obviously a pricing decision. An extended licence costs 62.79 € for a 10 assets/month and 50,4 € for a 750 assets/month subscription (if your indications are correct). I suppose you are referring to the 750 assets/month (I don't see a 720 assets/month, but different regions sometimes have different plans).