Hull cost 260000 × 90%[Close] × 150%[Reinforced] = MCr 17550.
You forgot 50,000cr per hull dt, (50,000*1.4*260,000)/ 1,000,000 = 18,200
You can't use 3 advantages on the jump drive since J-4 is TL13.
You can't use 3 advantages on a TL15 P-Plant on a TL15 ship.
Scoops cost MCr 1.
You have not calculated the cost of Holographic bridge?
You have not applied Energy Efficient to the M-drive.
Will have to fix those.
Why the CORE/70 computer? A CORE/100 would cold next to nothing.
Programs are only required for a specific step so doesn't require the extra processing power of the larger core.
And Point Defence software
Both designs have Point Defense/2 software.
The Reflec is hardly cost efficient in a Meson fight.
The most common weapon system is still the pulse laser which appears on most fighters, so its a good mitigation strategy as it pushes the upper limit of armor.
Reinforced hull is hardly cost efficient on battleships.
Given the only way to incease hull points is either by increasing dt or reinforced hull, the cost is rather efficient.
Why the screens and PD batteries? That few hardly have any effect.
Meson Screen x60 = 12DD reduction from meson weapons so nothing to sneeze at, considering its the only effective defense to a meson weapon due to meson weapons ignoring Armor.
Nuclear Dampers are also effective at stopping Fusion weapons in addiation to Nuclear weapons.
The laser turrets could use a tech upgrade, e.g. Long Range or Accurate.
The lasers are mainly for point defense purposes with a secondary purpose of engaging small craft at close / adjacent range.
The Particle Barbettes are the secondary system for engaging past close range.
The fuel processor is very small, it takes almost 5 days to process the jump fuel. That severely limits strategic mobility.
Considering most designs are designed between 3-5 days this isn't really an issue.
With budget drives you could make the ship bigger, cheaper, and have more hull points.
The point was to make the ship smaller and still carry the largest meson spinal available on the dread and the pocket battleship is designed with a similar setup versus battleship designs.
The dread could however go up to 300,000t to see if drive / fuel dt can be compensated for.
A military ship should have an Armoury.
That would more be the case if either design were to require heavy weapons or held a marine detachment which is dealt with at the escort level.