Online chess clock discrepancies

I'm running Windows XP SP3 and using Google Chrome ver 24 and/or FF 18. I've noticed in both browsers occasionally the time left in my online games will  increase as in earlier today my 2 games with the least time left showed 5 hrs left in one game and 11 hrs left in the other, but after visiting some other websites and coming back here now I had 6 and 12 hrs respectively. This isn't a problem (ie gaining time) per se but it does seem to be an interesting glitch, has anyone else ever noticed anything similar in their online games?

I have never noticed that, and it does seem odd.

The only time discrepancy I've seen is when an opponent gets low on time, say, an hour, as shown on my page. I'll occasionally go to their page to see if they plan on timing out or have just not been online. On their page, there will be more time shown for our game. Not a lot, always under an hour, but it makes me wonder.

Maybe each player has their own clock and the servers here also have separate clocks. At least someone in a forum about Live Chess time discrepancies claimed this is what accounts for the LC time discrepancies, although I think he was referring to LC time discrepancies.