I think the information you are looking for can be found in SAP note 2968880 - Filing status 00 is not valid on date MM/DD/YYYY - HRPAYUS_MESSAGES205.

I think the information you are looking for can be found in SAP note 3365473 - BEN: SECURE 2.0 Act - Section 603.

Per SAP Note 3124528-W4 Legacy Data-Changes in IT210, the withholding format of the original record is no longer determined by the begin date of IT210 and user can elect the withholding format record by the Original/Redesigned check boxes added on IT...