Was sorta asking to confirm my own plan.
Not sure at this stage,...however rather than obtain another retirement extension would go to Saigon and apply for DTV (soft power Medical).
The plan would be to apply ASAP after arrival in Saigon and stay a week.
Exit even if not approved at that point.
My main difference from your OP report would be how to activate the DTV.
Rather than border bounce would do second trip to Vietnam.
I'm biased as love Saigon