Does anyone know how WW2 German Tankers used the Piece Meal? chart which looks like a clock.?

I figure the Piece Meal chart has something to do with dealing with the threats in best possible order to optimize the best chance of the Tank/Tank crews success and protection.It may be something to do with the German tanks amor thickness against the range and power/size of the projectile. It is probably neither of the above, I have only seen it used by crews operating the Tiger 1 Tank (Panzer VI) so I don't know if this procedure is unique to the Tiger 1 Crews or common throughout the different Panzer Tanks and Tank Destroyers of Nazi Germany.