If I add an additional Dependent System to a Managed Domain Account, will the credentials for the Windows Service be changed right away?
No. If you add additional Systems to the existing list of Dependents on a Managed Domain Account, the entire list of Windows Service credentials will be queued for reset the next time the account password is changed. There are no changes in between.
More information on setting up Dependent Systems can be found in the TPAM Administrator Guide under the Accounts chapter.