Normally, I basically know approximately when "Next Update" is due and try to make certain my Computer is in "Idle" mode. Using less resources....as per my Update settings. As Ex Brit stated, the 2013 Version does indeed update differently. There has been on certain occasions,that I was about to go online, when an update was due within minutes, and like you went ahead and "Checked for Updates" with the same prompt appearing.
Having said that...McAfee still functioned properly and updated automatically later in the day.Like Ex Brit stated, I believe it was simply "Polling for updates"
In other words...I simply leave it up to "Automatic Updates" and all is "Good in the neighborhood"
After all Ex Brit is much more knowledgable than I....
You know you can go to navigation / General settings and Alerts/ general settings and deselect the Wait till idle option. Mcafee will start scans and updates immediately it wants to.