Socket Stone alchemy?

Hello everyone, I am wondering about socket stone alchemy. I do know how to make socket stones. My question is am I limited to what level socket stones I can make? Far as I can see I am only able to make up to high quality socket stones which are for 10th degree items. I want to know if there is a way to make Greatest stones 11th degree. I know that some NPC’s sell 11th degree socket stones but I run out of copper and iron coins fast. iSRO official game.