Well, that's pretty much explains itself. If your fence/fixer has the right connections, then he can sell that stuff for more, because he knows who'll pay a good price. If not? Well, he'll probably sell it to a ganger, or another fence/fixer.
I'd take Loyalty into account too. A Loyalty 1 fence will probably cut out a juicy piece (like ~70%) of the deal. A Loyalty 6 fixer will do that for a small fee (5%?) or even for free (for his best buddy).
