A point of clarification please.
As I understand your question, you have a server test bed under A/D, and you want to force the dates ahead manually, so that different points of the business cycle (calendar-wise) can be seen. For example, producing monthly reports within days of each other, and quarterly reports within weeks.
If they are hoping to do this on a production network, they are out of their minds. If it is an isolated test bed, then they might be able to do that if the date increments are small enough. They MUST fit into the Tombstone lifetime at the very least, which I believe is 24 hours.
I don’t know enough about the internals of A/D to say for certain, but I do recall learning shortly after NT 4.0 came out back in 1996 that a given system which did not communicate with the Domain Controller for some period of time had to be removed from and added back to the domain.
A fair number of Google searches for “Increment AD Clock” etc. failed to produce much, but I only spent 15 minutes on it.