There is some inconsistency between UnitVc, and the Unittext field in INVc.

In UnitVc, Code is M4Code with a 5 character limit.
In INVc, Unittext (and Unittext2) are M4Str with a 10 character limit.

Is there any particular reason why these are different? On saving an item, it checks that the unit exists so it's not actually possible to save an item containing a unit with more than 5 characters, however it does allow saving with a lowercase unit code, which looks a bit odd.