Seed
The only thing Michael had to do when expanding his Soul Sphere was to pick the location of the newly forming Empty Soul Socket. The position would determine how many SoulStar Fragments were required to create the Empty Soul Socket.
[You will form a Soultrait Symbol by combining a bunch of Soultraits, right? In that case, you should put the Soul Socket near the center. You know how troublesome Sphere of Elements has been. It's only in the middle area where the upgrade costs are up by 75%, but it's 22 times more expensive to upgrade than Extraction and Insert. Even Cosmic Stride in the Inner Area is only three times more costly than ordinary Soultrait Upgrades!]
"I know, I know. The Healing Soultrait will be in the Inner Area as well. Don't worry," Michael murmured right before accessing the dust-collecting pile of SoulStar Fragments.