[SS] A few questions about SM and armor scaling

[wellspring]

I'm working on a campaign idea and was playing with the Spaceships system, when I noticed a few things and I was wondering if someone can answer a few questions.

Most armor seems to follow the 1/1.5/2/3/5/7/10 progression, but for very low end armors the rounding on 1.5 seems inconsistent. For streamlined steel hulls, you have NO at SM5, followed by 1/2/3. Which means that 1.5 was either skipped or 1 was rounded down to zero. For stone, it starts with SM7 and goes 1/2/2/3, implying that 1.5 was rounded up. Ice starts at SM8, but progresses like Stone.

Then in Spaceships 7, Wood and Etherwood follow an entirely different progression altogether. Adamant and Skystone scale in a manner similar to steel, while Orichalcum has its own entirely idiosyncratic scaling.

The thing is, for things like Steel, the weird rounding differences seem to have little or no real significance. To the point that I thought they might be typos.

I'm asking because I suspect that a lot of thought went into these values and before I start monkeying with them I was hoping that someone involved in the project or playtest could shed some light onto why they behave the way they do.

(I've a few other questions, but this one will suffice for now.)