The Belongs to Month in Pay Frequencies is only used for the Payroll Tax Wages Report.
If you use the Payroll Tax Wages Report, you can change the Belongs to Month in Pay Frequencies for the current Period End Date only.
To change the Belongs to Month for a processed Period End Date, you will need to restore to before the End of Period was processed. You should take another backup after changing the Belongs to Month and complete the End of Period again.
To change the Belongs to Month:
Go to Payroll, Maintenance, General, Pay Frequencies.
Edit the Pay Frequency.
Select the correct Belongs to Month for the current period end date.
Click OK.
You can also change the Belongs to Month for the next Period when you are completing the End of Pay process.