QUESTION: I have a severance plan that provides a month of employer-paid health care coverage for each year of service as of the participant's termination date.  I am valuing it as a life annuity to member in OPEB mode.  How can I get the annuity payment period to reflect a fractional, rather than whole, number of years?

ANSWER: Zero out the benefit when the fractional temporary period is up, as in this expression for the Gross Benefit Definition:

YRS:= [#FLOOR (#DECSVC / 12)] &
MO := [(#DECSVC / 12) - YRS] &
DUR:= #PMTYEAR - #DECYEAR &

[CLAIMS * (DUR < YRS)] + [CLAIMS * MO * (DUR=YRS)] 

Note that this approach can be applied to value a severance pay benefit of salary continuance (rather than a lump sum payment), as in this example where one week's pay is provided for each year of service at termination:

YRS:= [#FLOOR (#DECSVC / 52)] &
WKS:= [(#DECSVC / 52) - YRS] &
DUR:= #PMTYEAR - #DECYEAR &

[SALARY * (DUR < YRS)] + [SALARY * MO * (DUR=YRS)], where SALARY is a Basis Only accrual definition Benefit Formula Component whose basis expression is #SALARY.