It should be but when I change a sidebearing of six, the nine's also changes. So it is somewhat misleading.
Now two steps are required to achieve inheritance: 1. disabling alignmnet 2. putting =| formula.
Components are positioned according to there origin point. If you change the left side bearing of the base glyph, the outlines change the relative position to the origin point. This affects the side bearings of the component glyphs. Thats why I implemented the automatic alignment.