I am wondering about this too. I forgot to backup my router traffic data for Jan and Feb when I was tinkering with DD-WRT firmware but with just the past few days for comparison and knowing what I downloaded in the past few days either the built in bandwidth monitor for DD-WRT is really that bad (I know it has trouble sometimes) or can ATT be monitoring it wrong?
Now that question kinda makes me lean towards ATT monitoring wrong since Brael you are saying it is coming in low for you and it seems ATT is coming in high for me.
I know DD-WRT isn't perfect at bandwidth monitoring at times but is it really that much off?
DD-WRT March 12 - incoming: 10999MB / outgoing: 840MB
ATT March 12 - downloaded:18.73GB / uploaded: 2.10GB
DD-WRT March 14 - incoming: 2289MB / outgoing: 291MB
ATT March 14 - downloaded: 4.95GB / uploaded: 0.51GB
DD-WRT March 15 - incoming: 11835MB / outgoing: 801MB
ATT March 15 downloaded 14.64GB / 1.31GB
I have gone over the 150GB cap twice now in their monitoring site which I know I have, and actually have gone over it for over 5 months now. I am wondering is the ATT monitoring site even reliable?