What NAVPERS form must be signed upon completing an extension?

The correct form to be signed upon completing an extension is the NAVPERS 1070/621. This form is specifically designated for documenting an extension of enlistment in the Navy. It serves as an official record that reflects the changes in the member's enlistment period and is essential for maintaining accurate personnel records.

This particular form is crucial because it not only confirms the agreement to extend service but also ensures that all the necessary administrative protocols are followed in compliance with Navy regulations. Proper completion and signing of NAVPERS 1070/621 help to maintain clarity and legality in the member's service commitment.

The other forms listed are associated with different aspects of naval personnel records, such as service record updates or different types of enlistment or reenlistment documentation, but they are not specifically designated for recording enlistment extensions. Hence, NAVPERS 1070/621 is the appropriate form for this situation.