I've been wondering, some tasks that 7/9 performs in Astrometrics, it would seen, are easily accomplished from some of the bridge's consoles. Scanning for enemy ships, scanning a planet's surface, scanning for lifeforms, to name a few examples, either Kim or Tuvok do it often from their consoles. Also, in the episode "Omega", when Seven builds a containment chamber for the particles, that task seemed more appropriate for engineering I believe (actually during the episode there's a little feud between BElanna and Anika, which proves my point). Which leads me to the question, isn't there some duplicity in functions, operations being performed in Astrometrics vis-à-vis the bridge/engineering? I know the Astrometrics lab was built specifically for Seven (since BElanna would not accept her in engineering) and she needed a domain where she could put her infatigable borg efficiency to use, even if that meant taking attributions or functions that belonged to other departments.