I brewed a Zum Uerige homage beer (1.048 OG) on Saturday (5.5 gallons); pitched two packets of 34/70 by sprinkling on top of the wort (at around 2 pm @ 54F) and it was showing no gravity change after 18 hours, but sometime thereafter, it started rocking. That is, I didn't worry about it and this morning (Monday) the gravity reading was 1.034. I suspect it will be done in about 6 days total, as usual. Fast start, fast fart....YMMV and it probably won't be much of a final difference. I know that when I re-pitch, I get a very quick start with just about any yeast, but that is probably the nuclear weapon analogy that S. Cerevisiae always talked about.