Postei minha pergunta no link .
E aqui está a resposta que tive de Jesper Stähle , obrigado para ele:
"Hi,
The limitation is about AD-objects. Short answer to the question you have been asked is:
"No."
The limitation is not regarding users in the tenant (enabled or disabled), it regards objects in the on-prem Active Directory (Groups, Contacts, users combined). To be able to syncrhonize deletions, deleted user accounts in AD also Counts.
If you are close to 50K in local AD - I suggest you raise a support ticket stating that you might have more than 50000 AD objects that will be synchronized so that Online Services team can prepare your tenant for this. Also, you should make sure that DirSync is deployed with a full SQL installation for the configuration: technet.microsoft.com/.../jj159544
Also, if you have not already runned the Deployment Readiness Tool, I suggest you do so and analyze the outcome from that: community.office365.com/.../8155.aspx
Best regards,
Jesper Ståhle"