I've noticed the same thing. I think the lag can sometimes be caused by someone else in the game. It usually happens to me right before Iget a message that someone has lost their connection. As for the low pings only, I've gotten that message too but have no idea why. All I know is that with my cable modem, I usually get pings around 40-60 but sometimes get as high as 80 or even 100 or higher. I think that message comes up when (for whatever reason) pings go unusually high. I know almost nothing about how the internet works so maybe someone with more knowlege can give a better answer than I can.
When a very slow modem player goes in a match in mp with like cable or DSL players the ping goes higher to syncronize the speed with the slowest player with the fast players. When I play my ping is around 300-400 average.
Tie's Kindle Reading Project
"Making myself a more learned person and then bragging about it."
Since October 2010 - I'm a slow reader
27 Books Completed
('10: 4, '11: 9, '12: 7, '13: 6)
Fiction: 12 | Fantasy/Sci-Fi 5; Classics 3; Literature 4
Non-fiction: 15 | Investigative 2; History/Politics 3; Science 3; Biography 7
11,865 pages (approx)
Last book: Cosmos by Carl Sagan - Dec 2013