The cogwheel on the pump shaft has 12 teeths, meaning the rotor arm position
(together with the distributor shaft) can be adjusted with 30 degree discrete steps.
I think the compensation of the orientation is solves the ignition timing,
but the rotor arm might be in inaccurate position when the spark is fired.
Maybe i'm wrong, but i think it's might possible when the rotor arm is not exactly point
towards the corresponding cylinder's segment in the distributor cap @ the moment of the ignition.
You can check this by removing the distributor cap @ TDC, and the rotor should point exactly to
a segment in the rotor cap. If so, that means i'm wrong, and it's not an issue.
If not, the spark is forced to longer route, which eats up the ignition
energy towards the spark plug, and heats up the rotor arm.