Those clocks are sophisticated instruments that calculate...

Those clocks are sophisticated instruments that calculate time by measuring electrical charges called coulombs -- given the rapidity and volume of electrons that move through the measuring device the calibrator must adjust at certain points which was the delay you see -- the delay is just recalibrating for the clock moving too quickly during the 10 -- 10ths of a second before the delay -- this insures that the actual playing time during a period is exactly 20 minutes That is not an opinion -- that is science -- amazing devise quite frankly.