It's not about rank.
It's about how important the work that is given to each drone that can be trusted to do well because there's a spectrum of how good each engineer is and who can be trusted to do good work more or less than the others.
Considering Harry's Hissy fit he certainly thought it was real slap in the face.
SEVEN: Crewman Dell, I'm assigning you a task more suited to your abilities. Calibrate the ionic pressure seals on the observation ports. Your new designation is Three of Ten.
DELL: Yes, ma'am.
NEELIX: I've got more isolinear processors for you to install.
KIM: Thanks, but I need to get the power relays online first.
NEELIX: Are you sure that's a good idea? Ensign Wildman was assigned to that.
KIM: This is ridiculous. I'm not going to waste time just because Seven wants to turn this team into her own private Collective.
NEELIX: She says it's more efficient.
KIM: Maybe for a bunch of Drones.
SEVEN: Six of Ten, this is not your assignment.
KIM: Please, stop calling me that.
SEVEN: You're compromising our productivity. I'm reassigning you to chamber maintenance. Your new designation is Two of Ten.
KIM: Wait a minute, you're demoting me? Since when do the Borg pull rank?
SEVEN: A Starfleet protocol I adapted. It's most useful.
KIM: I'm glad you're not the Captain.
CHAKOTAY: How's it coming?
SEVEN: The crew can be quite efficient when properly organised. The harmonic chamber will be completed within the hour.
CHAKOTAY: Good. I'll let the Captain know.
SEVEN: Has she retrieved any new data from the surface?
CHAKOTAY: Not yet. They're still trying to access the primary test chamber.
SEVEN: Were there survivors?
CHAKOTAY: A few. The Doctor's treating them in Sickbay.
KIM: Commander. Seven's taking this hive mentality just a little too far. Designated functions, numbered Drones. I wouldn't be surprised if she started plugging us into alcoves.
CHAKOTAY: When in the Collective, Harry, adapt.
Okay, demotions go down. And she assimilated the tactic from Janeway... Who had Janeway demoted in Season 4?