Looking for guidance on how to set up deduction calculation based on age

I need to set up a voluntary employee paid accident insurance that is based off of employees age.  Depending on the employees age will determine the amount (which is a flat amount per age category).  I also need to do one based on spouses age (the age is determined not be DOB but by the AGE and FAGE fields respectively).  Has anyone set up something similar, and if so, what table method would I use to set this up?  Thank You.