I certainly hope you willing to apply that logic to everything in Disco Thyrzul, it would be quite hypocritical if everything else that makes no sense got a free pass, I eagerly await your entire rework of the mod.
I can agree that freighters carrying 500 passengers is excessive, which is why I suggested making them a uniform 2 units. The biggest oversight here is forgetting that liners have rooms not holds and by that standard each passenger should take up a single room. However that would be incredibly dull and uninteresting, althought it would make profit calculations far simpler.
Nothing changes in the maths but there is a very distinct lack of grandeur when you pick up 200 passengers compared to 4,000, hell a double decker bus can hold 80 people and I'm fairly certain our liners are slightly bigger.
As I said the first time, I can agree that the amount some ships hold are a bit extreme but the proposed idea is equally extreme.