I was taught to understand 'keep the prop on top' was referring to the order of lever movement when increasing/decreasing power.
I know the idea is RED/BLUE/BLACK, but to be honest it really would not matter for the few seconds if you had a moment where detonation might get close to happening.
It is almost an old wives tale too, except that there is a small amount of theory that suggests you could get close to a detonation limit in some cases if you left them in a particular way.
Refer the other thread..........