It appears that "Anwartschaftsdynamik" here means "rate of pension increase during the qualifying period/waiting time/expectancy" and "Rentendynamik" means "rate of pension increase during the pension period/benefit period/retirement period". This is backed up by this explanation in German:

http://members.aol.com/RoseKoedel/Altersvorsorge/GGF-Versorg...

Anwartschaftsdynamik (Steigerung der Rentenansprüche vor Beginn des Rentenbezugs) - In der Rechtsprechung wird insbesondere im letztgenannten Urteil zum Ausdruck gebracht, daß die prozentualen Erhöhungen von Rentenanwartschaften (im Urteil 1%) keine ungewissen Erhöhungen i.S. des § 6a EStG sind.

Rentendynamik (Steigerung ab Rentenbeginn) - Nach BFH-Urteil sind fest zugesagte prozentuale Rentenerhöhungen (im Urteil 2%) keine ungewissen Erhöhungen i. S. des § 6a EStG und damit steuerlich anzuerkennen.

K.-H. Stocks – Wörterbuch fur alle Sparten der Versicherung, Reinhart von Eichborn – Der kleine Eichborn and Hamblock/Wessels – Großwörterbuch Wirtschaftsenglisch all show "expectancy" or "qualifying period" as a translation for "Anwartschaft" in an pension insurance context.

The above dictionaries plus Dietl/Lorenz – Wörterbuch für Recht, Wirtschaft und Politik indicate that "dynamisch" means "index linked" in an insurance sense.

The term means that the pension moves up (or possibly also down) in relation to some index, e.g. consumer prices (CPI), net wage index (often used in Germany), inflation rate, or a percent of the present salary of a person holding the same job. This movement takes place both before the worker is eligible for her/his pension and during the pension period

BUUUUUUUUUT, there are almost zero or zero pertinent Google or AltaVista hits for "expectancy index", "pension index", "qualifying period index", "waiting-time index", "candidacy index" or "claim index". If any of these terms were correct for your context, one would think there would be many insurance and government site hits for them. Adding the term "linked" only made the search results even more disappointing.

Changing the order of words leads to some pertinent sites, such as:

"indexed pension" (often used in Canada, Australia and Ireland)

http://www.superannuation.asn.au/dictionary/p/pension.htm

http://www.austlii.edu.au/au/other/ato/itr/it2620.html

http://www.ireland.com/newspaper/ireland/2000/0415/hom20.htm

http://www.ccsd.ca/finbrief.html

"indexed retirement (plan)" (often used in the US)

http://www.bcs-group.com/programs/4.shtml

Harvey W. Rubin - Barron's Dictionary of Insurance writes about "indexed life insurance" with which the monthly payments after maturity are adjusted for changes in the CPI.

As I have not been able to find short English terms for this context, I might be forced to write:

"The calculation(s)/figure(s)/estimate(s) is(are) based on the following trend assumptions: an interest rate of xx%, a rate of benefit increase during the qualifying period of xx% and a rate of benefit increase during the benefit period of xx%."

HTH

Dan