I'm not sure we're talking about the same thing. Could you do the following?
1. Post Phantasmal Chorus rank
2. Post total Music Buff Effect (ie: +10 from r6 Playing Instrument, +8 from upgraded Battle Mandolin; +18 total)
3. Activate Meditation
4. Activate Hymn of Life using March Song while at 10 stamina.
5. Wait out the duration and post current stamina.
Oh sure I can test that out later.