Multiple echo sources/elements?

[sonickles9]

Supplemental damage works per damage instance, and as such multiple echoes (bonus dmg) effects all get the supplemental damage bonus.
Current implementation doesn't make it clear whether if the party echoes and individual echoes are separate, but either way it is not capable of accurately calculating multiple sources of echo, neither various element echoes (such as Narmaya/Morphe and Phoebe/Monika (Grand)'s superior elemental echo, and Sandalphon (Alter)'s 4-element echoes).
It could be like the way crit is currently implemented, for example.