As i fear i am getting no-where with customer service or the ''experts''(****...shock, horror). I am going to make this bug public here. Do not use seige bat 3 or 4 on any of your hulls, if these specials are on they need refit imediately for either garrison battery or frontline counter sys as these are the only specials where the 50% turret defence bonus is actually working.
Took alot of refits and narrowing down this bug, but i can confirm that this is true. Originally noticed it last month when i won my 2 kings writs...One was taking damage to omegas, the other wasnt. I set about determining the cause of this and after alot of wasted shipyard time and tokens i can say with confidence the seige bat 3 and 4 do not give a 50% turret bonus. I had 1 defensive writ with counters and frontline counter sys ... thats working fine no problems... the one with seige bat took damage to omega on either the 3 or 4 versions of the special...i refitted garrison battery now and it is just fine again to cut a long story short
(note: yes i used a brennus sloth lead hull)
On the way i learned evade has nothig to do with it, tactical field resistance has nothing to do with it, the amount of special slots filled has nothing to do with it.....<---hence my wasted shipyard time and tokens
Seige bat 3 and 4 are basically useless specials which are also lying in the statsblocks too, dont be fooled.