Interesting tick

Interesting thing I note with the 2500 movement. The tick is normally very quiet. However when I lay the watch on a hard surface with the 9 o clock side down it becomes audible from several feet away. The interesting thing is that it is only audible when the second hand is at 12 or 6, I.e going up or down towards gravity. It is silent when the second hand is at 9 or 3, I.e. moving sideways parallel to the table. From this I assume what we actually hear is not the escapement directly but rather the gear train carrying the sound as it takes the weight of the second hand in the horizontal position. When the second had is at top or bottom the gear train is largely unloaded. Do you agree? Other explanation?

I guess you guys have noted this already, but it was new to me...I lead a quiet life I guess.