Let's say I have a weapon with 1000 ballistic damage to both ships and buildings... a special that gives +50% ballistic damage, and a second special that gives +50% building damage.

The damage to ships seems easy to calculate, it's simply 1000 x (1 + 0.5) = 1500.

However, when it comes to the building damage, does the bonus building damage only apply to the base damage of the weapon, meaning that bonus ballistic damage is only used for calculating damage to ships? Or does it all stack together? And if it does stack, is it additive, or multiplicative?

A. building damage = 1000 x (1 + 0.5) = 1500?

Or

B. building damage = 1000 x (1+ 0.5 + 0.5) = 2000?

Or

C. building damage = 1000 x (1 + 0.5) x (1 + 0.5) = 2250?

The damage to ships seems easy to calculate, it's simply 1000 x (1 + 0.5) = 1500.

However, when it comes to the building damage, does the bonus building damage only apply to the base damage of the weapon, meaning that bonus ballistic damage is only used for calculating damage to ships? Or does it all stack together? And if it does stack, is it additive, or multiplicative?

A. building damage = 1000 x (1 + 0.5) = 1500?

Or

B. building damage = 1000 x (1+ 0.5 + 0.5) = 2000?

Or

C. building damage = 1000 x (1 + 0.5) x (1 + 0.5) = 2250?

0

Siege Mortar D85-Dbase damage = 5800

salvo = 2

reload = 5 seconds

Monolith Aura+20% explosive damage (x4)

High Yield Warheads+75% building damage

Precision Napalm Detonator+20% explosive damage

20% chance fire field for 1200 radioactive damage

Garrison Battery Mk-X+18% explosive damage

+65% building damage

If bonus building damage does not stack, then I see no reason to ever use Precision Napalm Detonator, as the extra 20% explosive damage does absolutely nothing to 90% of the targets in the FM.

However, if they stack additively, using Garrison Battery and a fleet of 4 monos gives...

building damage (with PND) = 5800 x (1 + (0.2x5) + 0.18 + 0.65) + (0.2 x 1200 x 2) = 16414 explosive + 480 radioactive

ship damage (with PND) = 5800 x (1 + (0.2x5) + 0.18) + (0.2 x 1200 x 2) = 12644 explosive + 480 radioactive

building damage (with HYW) = 5800 x (1 + (0.2x4) + 0.18 + 0.65 + 0.75) = 19604 explosive

ship damage (with HYW) = 5800 x (1 + (0.2x4) + 0.18) = 11484

So if this is how it's calculated, you get about 20% more building damage using HYW, while only sacrificing 10% damage against ships. This seems like a big win, given that most of the targets in the FM are buildings. And if you take this one step further, and assume that bonus building damage is stacked multiplicatively with bonus explosive damage, then HYW is even better.

And if you don't need that much extra splash, you could even roll with High Velocity Rounds, which will get your mortars to the target twice as fast, AND give you more bonus building damage than HYW, at the cost of 60% less splash, however much much less weight, meaning you can carry better weapons, better armor, etc.