I think we're having a differing of opinion here. Being enslaved to the same family for so long Joseph's attachment to the blood line runs deeper than a normal even hard broken slave. The continual link to the same bloodline would make the re-breaking process quite difficult. It is, by the nature of such a long break, almost a part of his very make-up to serve the Vandros, and the loyalty to them would be excruciating to lose. The break would likely cause Joseph some major issue for a long time, and if not treated, permanent damage. I would say that, written in a manual somewhere, that trying to transfer a slaves bound via the breaking potion for over a certain amount of years to the same family is not recommended.

Tell me this: What is the value to you of a stamp that was originally purchased for 2 cents fifty years ago from a bank, in excellent condition, that only has thirty others like it ever printed, and only 10 of which are in the trading market?(Inaccurate example of the price of a stamp 50 years ago, but it's besides the point) Nothing, right? It's a stamp. But to a stamp collector, that stamp may very well be the holy grail of their collection. That is how collector minds work. *Nods* It's not what he can do as a slave that makes him valuable, it is making him "My" slave that has all the value :P