If a client have a maintence window at 1am - 2am and the deadline have happend before or at 1am the client will install the patches, it will not include the 2 hr randomization if you disable that in the client settings.
You could also use a deadline at 1am and don't use any maintence windows, but you should be aware of if a client is off at 1am it will start to install the patches asap when the client has started again.