Natural Volume is a function of MIR Pro, and has nothing to do with settings in VI Pro, other than the instrument it detects.The Flute PRESET, does set the VI Pro volume to 118, but loading a Flute Patch does not change or set any volume.
It looks like maybe you are just confusing yourself here.
If you want to use Natural Volume with these Presets:
/A - Strings PRESET - Files/01 Violin solo/VI VSL Preset Level 1 and
/B - Woodwind PRESET - Files/32 Flute I/FL1 VSL Preset Level 1,
how would you set Volume in VI Pro for the flute Preset? Would you have it at 118, where it defaults when you load the flute Preset? Or would you have it 127, to match default VI Pro Volume for the violin Preset? If you want the natural arrangement between the violin and flute timbres, you have to choose correctly between 118 and 127. If you choose wrong, you will not get a natural arrangement between the violin and flute timbres. What do you choose?
Please unconfuse me, if you know which choice is correct for attaining natural arrangement between the violin and flute timbres?