The electrician who installed my new panel (200A CH), he not only doubled up on connectors / knockouts, but also used several shared neutrals in runs from the panel to J-boxes just above it to connect with wiring that would not reach the new panel.
He used 14/3 or 12/3 cable then split the circuits in the J-box.
I believe, but I am not sure he has these circuits on opposite legs. I need to check this out next time I go in there.
Hopefully he did keep track of the wires. Theres nothing wrong with mini mwbc extending to j-boxes above the panel to feed short lines.