Yep, just when you have this tricky beast and it's timings all figured out - beware, it can, and so often will, throw a completely unexpected curveball at you, even after 20, 30 or more years of entirely reliable, predictable precision timing accuracy. This'll go for cycle timing, time of day/night when hits can be expected, and other stuff not related to timing, like one of the biggest shockers I've learned of - switching to the other side of your head (!!!).