Kernrechtsfrage
Whether the pension fund had to calculate the invalidity pension under the 1990, 1997, or 2009 regulations.
Extrahierter Entscheid
The 1997 regulation governed the initial reduction; the 2009 regulation could apply to later coordination under its transitional clause.
Extrahierte Begründung
The wording and structure of the transitional provisions protected the previously acquired pension entitlement, not all future payments at the same historical level. The 1997 clause did not freeze actual payout amounts, and the older 1990 wording was not carried over.