Generally speaking, soul traits are quantified individually, but Mephit's three traits are intertwined, requiring them to be quantified together. Hence, the spiritual power strength needed is far more than just three times. Bossivale believes she might need to reach level 16 spiritual power to achieve quantification.
Advancing from level 15 to 16 spiritual power is a chasm. Even Rod struggled immensely to break through; without the extra strength provided by the Giant God Power, he wouldn't have reached this level.
This also marks the dividing line for a strong Monarch. Mephit, however, needs to reach this level to become a Commander in the narrow sense.
But she doesn't feel too lost. She doesn't seem particularly obsessed with her own power.
In contrast, Rod is very attentive, asking Bossivale for the complete steps to unravel her Soul Curse, preparing to thoroughly dismantle her Soul Seal, step by step.
