This requirement that needs one mark of bondage for one divine ability is something that cannot be changed.
A mark of bondage is needed to control a divine ability and slavers have not been able to get around it. Not even mastering the Power Bond divine ability will change this requirement.
The only thing that the Power Bond divine ability changes about the divine ability is the level of mastery that the slave master will have with the divine ability that they gained control of from their slaves.
A normal slave master will have six marks of bondage when they master the divine ability to 100%. One at 1%, 10%, 20%, 50%, 90%, and 100%. So they can either have six slaves or one slave and five divine abilities that they control.
For them with three consciousnesses in charge of the pathway, they will have 18 marks of bondage at 100% mastery. Right now, their mastery of the divine ability is above 50%, so they can have 12 slaves or one slave and 11 divine abilities.