mademetop - 1:48 pm on Jun 6, 2012 (gmt 0)
Almost certainly, when you repeat a visit to a website you are retrieving it from cached memory somewhere or even from a cache on your disk, perhaps. what you are unlikely to be doing is downloading an entirely new version of the page.
In this case your retrieval will be significantly faster than a brand new visitor. Google visits a page as a brand new visitor and, as a result, gives the avg page loading time as the time it gets - not what you get.