Licenses

Hi, this plugin is awesome. I’m going for the PRO version.

I just have one doubt. I need this plugin for three websites. But I will test in one first before make my mind to buy the $30 license. If buy the single site license for ten and want to buy the unlimited license one or two months after, I’ll must to pay all the $us30 license or just the $us20 for the difference?

https://wordpress.org/plugins/wp-content-copy-protection/