When I'm outside I typically get the full 5 bars. Inside work at my desk is around 3 and 2-3 inside my house.
I also noticed that my speed tests are greatly varying when the bars are lower as well, but only for download speeds. Really weird. I'll get maybe 64-128k down and 1mb up when showing 3 bars and 1.5mb down and 1mb up when showing 5 bars.
Any reason when the upload speed stays the same and download speed grinds to a halt when bars when I lose 2 bars? Really weird. I would expect that both download and upload speeds would get affected with a decrease in signal.