Goa, are you sure? Can anyone else confirm? The first mention I saw of turrets doing 40 damage was Auqia (Master1a) as an undocumented change in one of the last changelogs (1.32?). I could've swore it felt like they were doing double the damage. And now they've returned to pre 1.34 levels??
I'm sure. Go to your Sins directory, then Diplomacy, then GameInfo. If you scroll down to the PLANETMODLUE section, you will only see files for the hangar defenses and the pirate turret. That means Diplomacy does not in any way change the turrets, its using the exact same file from Entrenchment.
For those that aren't modders, this is from the Gauss gun file.
DamagePerBank:FRONT 120.000000
DamagePerBank:BACK 0.000000
DamagePerBank:LEFT 0.000000
DamagePerBank:RIGHT 0.000000
Range 6700.000000
PreBuffCooldownTime 6.000000
...
TargetCountPerBank:FRONT 1
In normal english, that says the turret does 120 damage every 6 seconds to 1 target. (120 / 6) * 1 = 20 DPS, as it has for all of Sins. Also all tactical structures have this issues, even ones in mods that could not have been changed by a Sins patch, so it was purely a display issue.