There's a need to do a reverse sync because flow will change. New accounts will be created in target environment now and will be synchronized to the source environment, and according to how Active Directory consume licenses, if the consumption occurs per source account, the licenses will be consumed twice?
For two-way sync, ODMAD licensing will not be consumed twice. Here's how ODMAD is consuming licenses:

And here's the list of object types, that will cause ODMAD to consume licenses:
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"How long does Quest retain the information about already synchronized user when license has been consumed?"
- Until the Client is off-boarded - Until then we keep track of the license consumption based on the source objectid attributes