DOC: Reference for income tax calculation of Vorsorgeaufwendungen

[MImmesberger]

In our code, Vorsorgeaufwendungen are calculated in a pretty complicated way because there are two regimes active at the same time: A "2004 regime" (basically the Rechtsstand before 2005) and the current regime of the policy date. We are missing any kind of legal reference for that.

[hmgaudecker]

There was a favourability check in place, though I am not sure whether it happened automatically or you needed to pick yourself in the tax declaration.