[Micah]

It gives a B1 mage a 40% greater chance to find slaves (90 as opposed to 50) and a B2 mage a 10% greater chance (100 vs 90) so you get some serious diminishing returns, but it still helps. Also, according to the formula given in the book (which is at least partially incorrect, as I noted) every time you do find slaves each level of blood adds an extra slave before the random element, so even on a high-level mage an SDR will be worthwhile after 6 successful hunts, at least if that part of the formula is accurate.