I believe they have to confirm all 3 and 4 star appointments, and those are just 'temporary', they have to confirm their retirements too (that was an issue when ADM Trost retired shortly after Tailhook '91, some wanted to make him retire at the two-star rank).
Flash is either wise beyond his years, has a photographic memory, or studies Title X in his copious spare time....
TITLE 10--ARMED FORCES
Subtitle A--General Military Law
PART II--PERSONNEL
CHAPTER 35--TEMPORARY APPOINTMENTS IN OFFICER GRADES
Sec. 601. Positions of importance and responsibility: generals
and lieutenant generals; admirals and vice admirals
(a) The President may designate positions of importance and
responsibility to carry the grade of general or admiral or lieutenant
general or vice admiral. The President may assign to any such position
an officer of the Army, Navy, Air Force, or Marine Corps who is serving
on active duty in any grade above colonel or, in the case of an officer
of the Navy, any grade above captain.
An officer assigned to any such
position has the grade specified for that position if he is appointed to
that grade by the President, by and with the advice and consent of the
Senate. Except as provided in subsection (b), the appointment of an
officer to a grade under this section for service in a position of
importance and responsibility ends on the date of the termination of the
assignment of the officer to that position.