In order to hopefully find out where I'm going wrong with AEGIS Fire Control, I designed a couple of ships, one with Defensive weapons, the other with PDS, and both having an ‘escort' variant with exactly the same weapons etc., but with AEGIS. I've noted how much SU each step takes and the ORAT for the weapons and PDS. I've also checked the weapon TL as well—each ship has three different weapon tech levels.
All weapons except the Missile Launcher are CRB weapons. The numbers in parentheses are the SU total at a WTL of 0.
Assault Cannon: R-8, 1x3+/1/5, Pr2 (44.8)
Heavy Cannon: R-8, 1x3+/1/3, Pr1 (21.6)
Medium Cannon: R-8, 1x3+/1/2 (10.4)
Light Cannon: R-6, 1x2+/1/1 (6)
PD Cannon: R-2, 1x2+/1/1, Dfn (3 total, 1 SU as Defensive addition)
Missile Launcher: MA 9, 1x2+/1/1, Seeker (12)
MEGALITH-class battleship
Hull 12 (2520SUs)
Engines: 2 (-408)
Shields: 3 (-432)
Assault Cannon: ABCD (SU 314/224/157, OR 280)
Heavy Cannon: ABCD x2 (SU 302/216/151, OR 270)
Medium Cannon: [ABCE/ABDF] x2 (SU 292/208/146, OR 260)
Light Cannon: [ABCE/ABDF] x4 (SU 336/240/168, OR 320)
Missile Launcher: ABCD x4 (SU 336/240/168, OR 294)
PDS: 12 (SU 84/60/42, OR 180)
OR 1604, DR 48, CRAT 278
SUs remaining (-1/0/+1): 16/492/848
Weapon Track start: 31
MEGALITH-E class battleship
As above but with AEGIS Fire Control added
PDS: 12 (SU 168/120/84, OR 360)
OR 1784, DR 48, CRAT 293
SUs remaining (-1/0/+1): -68/432/806
Weapon Track start: 32
GIGALITH class Battleship
Hull 12 (2520SU)
Engines: 2 (-408)
Shields: 3 (-432)
Assault Cannon, Heavy Cannon, Medium Cannon and Missile Launcher as Megalith class. Light Cannons and PDS deleted in favour of PD Cannons:
PD Cannon: [ABCE/ABDF/ACEF/BDEF] x4 (SU 336/240/168, OR 480)
OR 1584, DR 48, CRAT 276
SUs remaining (-1/0/+1): 100/552/890
Weapon Track start: 27
GIGALITH-E battleship: as Gigalith but with AEGIS
PD Cannon: [ABCE/ABDF/ACEF/BDEF] x4 (SU 448/320/224, OR 640)
OR 1744, DR 48, CRAT 290
SUs remaining (-1/0/+1): -12/472/834
Weapon Track start: 28