Isn’t this BS about the power reserve when the chrono is running? Anybody did a real test on this?
A speedmaster will run out of enough torque in the mainspring to keep the watch running sooner if the chrono is running, but nowhere near as much as that guy is suggesting. Usually when the watch stops running with the chrono engaged, stopping and resetting the chrono will result in enough torque to allow the watch to run for another hour or two.