Automatic Coverage Reduction starting at age 65

Hi -

We would like to automatically reduce employee coverage on their 65th birthday.

When an employee turns 65 yo, we would like to automatically reduce their coverage by 65%.  The coverage should reduce each year the employee is in the following age band - 65-69 yo.  When an employee turns 70 yo their coverage should be automatically reduced by 70%.

Is there a way to configure Oracle to automatically apply the deduction or will we have to create a fast formula?

Thanks in advance,

Kathy