Voluntary Life Insurance calculation setup

I need some assistance with our Life Insurance Setup.  We have had it set up the same way since our initial implementation in 2004, and now it's in need of revision.

We have always calculated both our company paid life (including taxable income reported to IRS) and our voluntary life premiums based on age using the IRS tax table as of the last day of employee's tax year.  Every January, we update the employee's and spouses age based on 12/31/current year for our calculations.  Our voluntary life insurance premiums also increased at this time because of age bracket increases.  Our carrier is stating that is should be calculating off of age as of 1/1/current year.  Dows anyone have setup where their different life plans are calculating differently?  Also, our plans have