I checked with our Lacerte team and got some expanded information. (I'll update the article as well to make sure it's clear). 

The schedule function is to check for any available updates but it won't actually install the update until you open Lacerte the next time and get that Update Available Prompt. That prompt is letting you know it successfully downloaded some updates and want's your Okay to install them. 

It's also best to make sure that the date and time the scheduler is set to run is when your sure the computer is on and connected to the internet. For example, if it's set to run at 4am and you turn your computer off or reboot it at night, it may not have access to the internet to check at that time, which would prevent it from downloading anything. 

There is a log in the scheduler that'll show you if it ran and what the status is. That may help narrow down what's causing any missed updates. Our support team at 1-800-933-9999 can help with that if there are any errors on the log.