Benefit Program Participation effective date in Job Data after Benefit Annual Enrollment

After benefits annual enrollment is closed, employees that get move to a new Benefit Program have their benefit program participation details page updated in Job to reflect the new benefit program.  What in the annual enrollment setup determines the effective date of this new row in Job?

I ask because we have our wellness/non-wellness rates for our medical plan driven off the benefit program (which then drives the wellness or non-wellness rates) and since the new effective date of the benefit program in Job was dated 1/1/2020 the new wellness rates did not take into effect the first payroll paid in 2020 because the pay period dates were 12/16-12/29/19.  In order to get the correct rates to be taken on this payroll we had to update the effective date of the benefit program participation details in Job to be 12/16/19.