[PTTG]

Going back to the OP, I'd generally caution that one should treat systems as written as the most highly engineered, most expensive version of the system. Variants should be worse than stock in performance and cost-effectiveness.

I base that on TL8 and TL9 spacecraft design -- for the near-term, spaceflight is so expensive that it makes little sense to skimp on the vehicle itself, aside from reductions in weight. A well designed contemporary spacecraft is as expensive per kg as possible.

Future advances will make space more accessable, and thus the spacecraft itself will (eventually) become the primary cost, at which point cost reductions become relevant, but for the most part costs seem extrapolated from TL8 stuff.

That said, contemporary spaceship design is bespoke and one-off, so you probably need to multiply costs by a factor of maybe (1000/(total number of ships in the production run)+1)? I'd have to actually do research to say for sure, but it's something like that.

Presuming that remains consistent into the future, paying more for a better system really means both getting a one-of-a-kind ship that's built for your needs specifically, and expressedly not buying low-cost components to do the job.