Does anyone have any suggestions for this? Many thanks!

I found this on http://www.divorcemag.com/c/c3/?financial/pension

If the marriage occurred before the date the member joined the pension plan, the date of marriage is not used when calculating pension values.

However, if the marriage occurred after joining the pension plan, the value of the part earned before the marriage must be subtracted from the total earned to the valuation date. There are two methods of valuing such pension accrued to the date of marriage.

The added value method looks at historical records of the terms of the pension plan and the amount of the accrued annual pension as of the date of marriage. The present value is then calculated as of the date of marriage.

The pro-rata method simply calculates a proportion of the value of the plan at the date of separation, the proportion being the ratio of the period from plan entry to marriage divided by the period from plan entry to separation.

In both cases, the result is subtracted from the value of the pension at the date of separation.

I guess that makes the Zeit-Zeit-Verhältnis the preo-rata method.

Many thanks Gene Man!