olcObjectClasses: user-defined ObjectClass has inappropriate SUPerior: "dcObject"

[Igor Shmukler <igor.shmukler@gmail.com>]

Hello,

I could not find anything exactly relevant quickly. Sorry to bother
you good folks, again.

I am trying to extend dcObject class in order to support a couple of
additional attributes. It is not working, and it appears that the
problem is not syntax-related.

Is what I am trying to do legal? Is dcObject a good way to go about my
goal of adding a DIT-level attributes?
Should I instead create another class unrelated to dcObject? If yes, why?

Below is my LDIF:
olcAttributeTypes: ( 1.3.6.1.4.1.4203.666.100.129 NAME ( 'serviceLevel' )
  DESC 'directory service mode. valid values are: trial, standard and premium'
  SUP name )
olcObjectClasses: ( 1.3.6.1.4.1.4203.666.100.2 NAME 'customDcObject'
  DESC 'Directory Domain Description'
  SUP dcObject STRUCTURAL
  MAY ( serviceLevel ) )

I should probably replace the last MAY for MUST. My attribute should
be mandatory.
Yet, it is probably not the reason for the error, is it?!

Please advise,

Sincerely,

Igor Shmukler