Defer changes push to server (not only 3 minutes as of now)

It would be beneficial to have an ability to defer the transport of changes to servers. Now it is some 3 minutes, but having to wait for transfer of settings for example few hours could benefit in some cases, mostly in cases where you use opendns.com to challenge yourself and since you know the password, you easily change settings when you feel like it.

In general, 3 minute rule (basically immediate tranfer) can be left with possibility do select bigger time interval on save. To be safe, this interval should also be applied when changing back.

An example:
1) I set content settings and select to defer the transfer 3 hours. I click apply and immediate (3 min) transfer starts, as this is the current setting.
2) Then I change some settings, hit Apply and I have to wait 3 hours for a change
3) Then I try to change some settings again and also the time interval to e.g. 1 hour. I have to wait 3 hours (current setting) to see the effect.
4) I try to change something again and now I wait only 1 hour.