Adjust frequency of Windows Time sync
If you really want to synchronize at a specific time, your best bet would be to set the automated interval to a very, very large number, and then use the windows scheduler to run w32tm /config /update. If I got this wrong, you can consult the official documentation.
You can specify the refresh interval only. It will refresh on that interval when the server is restarted, or the time service is restarted. You could make a scheduled task to invoke "w32tm /resync /nowait" to schedule the sync's to happen a predetermined times.