So, I can soul bond my duplicate 3star, to increase its level max. Is this a one time thing? Does it matter what level the base and sacrifice units are (ie, my level 5 base unit has a max of level 20. If I soul link it with a level 1 duplicate, that goes up to 22. could I do it again, or would I get a higher max if I soul-linked a level 20 sacrifice unit?)