@eniko @grumpygamer I'd like it to be 210 but I wouldn't be disappointed (much) if the rule was simply [base damage] × [base multiplier] + [bonus].

Without putting on my +3 Helm of FORTRAN and defining history-based or lore-based priorities for order of operation, either ([base] + [bonus]) × [multiplier] or [base] × [multiplier] + [bonus] are reasonable. The former is good if you keep additive bonuses low so they scale as you get better multipliers - that +3 Helm of FORTRAN stays relevant longer. If you want players to chase better gear and macguffins, leveling up that +3 to +30 to +300 and adding the bonus to the multiplied base stat is good.

As a non game-dev but as a system modeler, I'd advocate for using the damage calculation to reinforce what sort of gameplay you're trying to achieve and set player expectations accordingly (a clear and consistent rule, an opaque metagame for dedicated accounting nerds to decipher, etc.) More damage is always better, as long as it's going out and not coming in :)