So basically time stood still for an hour instead of, as nowadays, repeating the third hour of the day. I wonder if this was really the case or if it was just an "easier" way to explain it to the average Joe.
An old pendulum clock can be easily set forward, but you must not push the arms counter clockwise. The method I've used requires waiting for the ding-dongs at each hour and half hour when you turn it forwards, so just stopping the clock for 1 hour is certainly easier than setting it forward 23 hours.