There are some preferences that control how often we ask for updates, but I would need more detail on exactly what you are asking for.

Do you want us not to check for udpates as much or sooner?

We would want to be able to check for updates only within a specified time window after hours, as the workstations are in a frozen state otherwise for security purposes.

We do not currently have a way to do that. You could theoretically schedule the background update process to happen during certain hours:

https://firefox-source-docs.mozilla.org/toolkit/mozapps/update/docs/BackgroundUpdates.html#scheduling-background-tasks