In order to give you a bit of an idea when your four hours will be up, have a look at the POLC log file. You should see
RequestHandler::PollForMissingApps: Starting Poll For Missing Apps.
every four hours. Normally it'll be followed by
RequestHandler::PollForMissingApps: Completed Poll For Missing Apps, elapsed time 0 seconds.
(meaning that there was nothing to do).
However, if there is something to send, you'll see something like
RequestHandler::PollForMissingApps: Queuing the package YOURAPPLICATION, consisting of X modules in Y parts.
The next time that the poll takes place will be 4 hours after the last one, unless you change the registry as described here:
(which includes some pretty serious caveats about decreasing the poll interval too much!).