Payroll Definition Impact to Benefits Calculation?

We need to update our Payroll Definitions for 2026 and 2027 due to the way our pay dates fall on bank holidays.

Week 1 for 2027 should be Week 27 for 2026 as the original paydate is listed as 01/01/27 which is a holiday, so it needs to be updated to 12/31/26.  Due to that, all of 2027 need to updated. How will this impact benefit deductions? Will I need to adjust the plans or programs to calculate the payroll processing differently? Currently, we have ours set to deduct from 24 paychecks (as we have 2 pay periods that have 3 paychecks in them so benefits only gets deducted from the first 2 pay periods of the month). Changing the paydates/payroll definition for all of 2027 would make us have 27 paychecks in the year of 2026.