Well looking at some real life ships with small crews, such as the German Type 212 Submarine, which has a crew of 5 Officers and 22 Enlisted.
The "Captain" is stated to be an O3 (in German a Korvettenkapitän; Corvette Captain), it seems that it's not an unusual rank for German Sub captains to of this rank even dating to ww2 and earlier.
The Interdictor Dropship has an identical crew complement and ratio.
Given this it dose seem rightly that B-tech it seems has over ranked Dropship officers and perhaps to a degree jumpship officers given the preponderance of them seeming going with O5 & O6 ranks being their commanders, Given that O3 and O4 is far more reasonable given their stated crew sizes.
As such a Fed Suns Achilles (5 officers, 25 En) should have an O3 (Captain) as it's commander, and a quartet of O2 and O1s (Leftenant and Subaltern respectively). Note in most B-tech navies it seems they use Army ranks for their lower ranks (only having distinct naval ranks starting around O4), though a number do not seem to have separate naval ranks at all, and likewise an Avenger or Claymore with it's 3 officers and 12 En would have a O3 and a pair of more junior officers.
