If I remember correctly, and I'm probably not (

), another effect on Blood Hunting is the site frequency setting. I think this was done to balance gem production against blood hunting. I may be completely incorrect, but if that is acting like a scaling factor, this could be important. Of course, if this is EA Mictlan and Sauromatia, on base settings, then the setting would be the same.
I'm assuming population in all provinces was over 5k and the unrest was kept down. On the other hand, is it possible Luck Scale was having an effect? Or Magic Scale?
I'm willing, when I have the time, to set up a neutral test case for this and run with it.
Wyatt