@Hortus
@MasterSeedy
Just ran a test using a character with a big in game buff: Vandor Chewbacca who provides himself 80% more Max health with his unique. Conveniently he also has an attack based on max health so we can get some feedback on how much is health has increased.
Method A: Calculating his max health with mod benefits being added to in-battle bonuses (the way MasterSeedy had originally calculated) he would have 48,327 health.
Method B: Calculating his max health with mod benefits applied before in-battle bonuses (the way I suggested) he would have 56,302 health.
His special ability does damage based on 10% of his max health (based on SWGOH.GG). I have no CD on VC, so 150% CD. I did his special attack based on max health while he had 'prepared' (which does double damage) and hits twice.
Damaged Observed on Critical Hit (per hit): 16,129
Method A Critical Hit no defense (per hit): 10% * 48327 * 200% * 150% = 14,498
Method B Critical Hit no defense (per hit): 10% * 56302 * 200% * 150% = 16,891
So even with no defense to reduce damage in the calculated value, if mod benefits apply additive with in battle effects the calculated damage is less than the damage level seen in game. To me, it's pretty clear mod benefits apply prior to in-battle effects as the predicted damage aligns closely with what is seen in game.