Hello @Bob De Vivo ,
Thank you for posting here.
The two commands are different.
1.Add-KdsRootKey -EffectiveImmediately ==> will add a root key to the target DC which will be used by the KDS service immediately.
2.Add-KdsRootKey -EffectiveTime ((get-date).addhours(-10))==> It takes effect before 10 hours.
It takes effect before 10 hours, or you can set it to take effect after 10 hours. You can set the time according to your needs.
For example:
3.Add-KdsRootKey -EffectiveTime 03/06/2013==> It means the start time of this day 03/06/2013.
For example:
Hope the information baove is helpful.
Should you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou