Starships currently are limitted to a max of +20% attack boost.
Given that they have had a nerf in their damage, I think to compensate for tactics that boost damage that they become more in line with fleet ships, who have much more damage already yet are allowed to get +100% in damage. Right now, if you pursue a heavy starship game, the flagship lags behind since it already gives +40% and thus doubles the starship cap, thus I leave it behind.
I think their max boost should be increased, thinking +50% to make it so that both the Military Command Station II and the flagship II both have a benefit.