It could be because there have been a couple of patches issued lately and of course it also depends on what applications you have as part of your security suite because different components can update at different times.
Other than that I can't think of any particular reasons for it.
In regards to the delay of the McAfee Icon, this is at the request of Microsoft. To allow certain Microsoft Processes/Programs to load. This of course does not effect your Protection. I run McAfee Total Protection myself/Windows 7 Sp1.
On my system the delay is around 1-2 minutes before the Icon appears beside the system clock. Followed by the Windows Action Center (Flag) very shortly afterwards.