SymPlatform_Mac-NS-Universal updates too quickly?

Since reinstalling Norton back onto my Mac I've noticed that it takes less than 10 seconds to download and instal SymPlatform_Mac-NS-Universal as there is only around 10 seconds between plugging in the internet and the security log saying update successful.

I've been using a computer for long enough to know that even on the fastest machine software does not update software that quickly and this leads me to conclude that the software might be downloading the updates but it is not installing them. Therefore I have been reinstalling Norton 2-3 times a day to get the latest definitions.

Any thoughts/guidance would be much appreciated.

Thank you for your reply.

This occurs when i switch on my computer and I am not doing anything to manually instal updates, it says that SymPlatform_Mac-NS-Universal has updated successfully less than 10 seconds after I plugged in the internet.

When online, Norton checks for new updates every two hours, as it always has done.

Are you completely uninstalling/reinstalling Norton for the latest updates or clicking on LiveUpdate?  

When I check the weekly history, I see these updates happening every 4-10 hours.  That makes me wonder how often a complete update actually happens - and if some (faster) updates might only be incremental.

I don't always leave my computers on 24/7 but it would be interesting to check the update logs for a computer left on all the time.