[klingonopera]

That is correct, yes. I had erroneously understood that the author meant "all durations between 0 and 65535 ticks" as "any duration between the device's 0th and 65535th tick", my bad... Also makes this entire thread obsolete, but FWIW, one shouldn't be attempting to measure a duration that can't even be contained in the variable's bit width. Some workarounds would be to add more bits, slow down the tickrate or add overflow counters.