Devs made the crew settings without any real thinking done.
I've gone thru all of my NSS_subtype.upc files and just about doubled the amount of officers and petty-officers for each sub type to take into account the game counting CPOs (E-7), SCPOs (E-8) and MCPOs (E-9) as officers. This also has the effect of lowering the number of non-rated (untrained) seaman/firemen among my crews.
Total crew complements were carry-overs from SH3 I'll wager as they don't reflect the larger crew complements found on US fleet boats. Average crew complement in game is 50-60 where as in reality the crews totaled 70-85 depending on sub class.
The devs did fairly well with coding the subs, ships and armaments but "missed the boat" when coding the crews.