Question on siege equipment

[CarnageINC]

Do multiple siege guns add up bonuses or is one just enough? Are they also used during battles?

[PhilThib]

They add bonus due to their combat power (sum of artillery combat power is used for breach calculation). Only one bonus for the "Siege Expert" ability is used even if more than one gun is present.

They can be used in combat, but their initiative is low, meaning they shall be engaged after other (field) artillery usually.

[JacquesDeLalaing]

But the mortar/siege-bonus is cumulative with a sappeur-bonus and/or with a "siege-expert"-ability, isn't it?

[arsan]

I'm pretty sure an ability is only applied once, never added up if several units or leaders on a stack have them.
(Of course, abilities that apply only to a unit/brigade and not the full stack can benefit its own unit brigade even if there are several in a stack, but never twice on the same brigade)
But the two different siege abilities (siege expert and siege engineer) bonuses should be added up
Cheers
PS: this abilities list is somewhat old (AACW) but may be useful to see to what level abilities effects applies (stack, brigade/division, self unit...)
http://www.leqg.org/doc/aacw/listability.php5

[Pocus]

Technically, alike abilities will only stack if they have a different 'family' number.