Item property definition tables

[podborski]

Minor thing, but should all the definition tables for item properties contain (per item) in the Mandatory and Quantity rows?
Looks like this is common practice in HEIF but it is mixed in AVIF (see av1C)

[cconcolato]

I'm ok to harmonize with HEIF. I understand what (per item) means for Quantity but what does it mean for Mandatory? How can a property be mandatory for anything else than an item?