DarkPearl The mod's name is related to the true nature of the mod and not necessarily catered to an existing player faction. The Abh mod is a function and faction (ship classes) mod. See them under the terran group menu? Ship classes aren't that well supported by Cosmoteer yet afaik e.g. Bounty Hunter so the mod is just ready for it (since 0.4.4).
As a function mod it's a general mod so the division in faction isn't restrictive, hence, higher tech levels are allowed access to all lower ones. It's up to builders how they want their lore to apply to usage of parts. You are restricted if you actually use factions.
Each tech level basically represents a different civilization level, hence, a different starting point or just a continuation of a previous one. Just like in real life there's no point in tech level with a few percentile increase in capability. You don't invest 2-4 times more for each generation just for a few percent of gain. You invest for at least a 2x increase. This common economic and engineering sense is advertise by Intel's propaganda as Moore's law. Aside from that each generation has to be able to do things the other could not or offer new abilities or at least be 2x better at it. That's why there are no two parts in the mod with the enough commonality in code (that could be reused) except mirror, form, and size variation parts (and walls).
