Unless the players want to run a merchant ship, it doesn't matter if it works in terms of dollars and cents (or credits). The economics can be equally broken.
My aim isn't to fix starship economics. It's to create a real gameplay difference between first class and mid passage, to reflect that class-conscious Imperium in which social standing counts.
Well then that's different.
Make a SOC roll and apply depending on situation.
If rolling to buy a High Passage ticket, roll SOC or below to buy one. If you fail, you can't because all HP available are booked or you are unsuitable and have to buy a Mid or Lo Passage.
Roll again for a Mid Passage, same roll. Failure means Lo Passage only.
Then roll a SOC check-
- for Mid or Lo Passage use, roll below SOC and you incur a SOC-1 hit.
- for High Passage, roll 2d6, if you roll at or below the number of trips at High Passage in a row, roll against SOC- if you roll above your SOC you gain SOC +1. You cannot gain peerage in this manner.
The latter is effectively social climbing on the travelling party circuit, paying to see and be seen.
This is where Admin, Bribery, Persuasion, Liaison, Carousing come into their own as a SOC-conscious character may be desperately trying to secure a way off-planet, but it has to be the RIGHT ticket- or maybe they use the above plus Deception to fly incognito and avoid the SOC penalty.
Do all the skullduggery up front and apply the DMs to the roll. If HP is failed to be bought, the character cannot try again for a week. They may have to wait and deal with the consequences of being onworld, sneak out as not themselves, or risk SOC hits.
This is the sort of thing a class conscious society would do- people would rather DIE then be seen in a second class conveyance with the 'wrong' people and lose status. And lower classes end up in Lo Passage with it's inherent risks.
TAS is an exception, the High Passages are automatic and you are essentially vouched for even if your SOC is low due to your service to Travellers, but this indulgence also does not allow for interstellar social cliimbing.
That help with your intended effect?