I pitched a Wyeast Propagator that was about 4 1/2 month old into a liter of starter. Due to the age of the yeast obviously I wouldn't have 100% viability - assume for discussion sake its only 20%. I'm going to step it up by decanting the liquid and re-pitching the slurry. Since I'm pitching the yeast that grew from the original Propagator is it safe to assume this "2nd generation" of yeast has closer to 100% viability?