Insta-flashed my MN03 that only had ~2 hours on it. Two haven't hurt my KL4, but it is darn hard to measure the applied voltage at startup. (Does the KL4 circuit have a cap on the input?) I have switched to a Mc2e two stage tailcap on my L4 for convenience, battery life, AND insurance against high startup voltage on these batteries.
I expected the Batteryspace cells to come off the charger at 3.7V no load, and be ~3.2V under load. No load voltage straight off the charger is 4.24V !! This is enough to kill some of the microcontroller based LED lights, if the few uA the microcontroller draws in the "Off" mode is not enough for the batteries to regulate down...