Detmer wears
bronze, so she's engineering division. Helm is also seen wearing engineering colours in the TWOK era, so it seems to be an area which swaps in and out of different divisions over time.
Agreed. While the US Navy clearly provides a template, we have tried too hard at times to line things up perfectly. There are numerous places where they don't overlap exactly and it seems odd when some insist the US Navy reality must take precedence over what we've actually seen happen in the show (like that debate the other day about length of time spent in one post). In this case though, I think that the comparison to real life is valid, and Trek has mirrored the idea of officers who are high ranked but not in the chain of command. Crusher is a good example, she is equal rank to Riker throughout, but we only see her in Command much later on when she's done the Bridge Officer test. We've also seen the opposite where "bridge officers" (like Lt j.g. LaForge or Ensign Kim) are given the Bridge over higher ranked alternatives.