NVG510 Only .35 Upload; Should be .7

I have recently upgraded my account from .7 down and .35 up to 6 down and .7 up--I would have done it much sooner but the option just became available to me. However, I am only getting .35 up, I do get the entire 6 down most of the time according to speedtest (ATT's, speakeasy, speedtest, and my local NetSpeedMonitor application). Every speedtest will show my upload quickly go to .35Mb/s and just hang there, never going higher. It feels/looks like my .35 cap is still in place, but from my sync rates the modem is saying that isn't true.

I have called ATT and after a few test they don't know what the problem seems to be and seem to think that i should just pay 100 dollars for a new modem--which they cannot say will fix my problem for sure. I am hoping there may be a better way to determine the issue. I have run all tests with just one system connected to the Modem (wired) so that i can rule out other simultaneous uploads. I cannot find any special settings in the modem itself that wold be limiting transfer speeds, so i am stumped.

Below are my Broadband stats--which you can see the modem is listing at the correct Sync Rate:

I have tested local traffic through the modem and i have no problem transfering files at over 12MB/s or more to other systems on my network. So the modem seems to be fully capable of handling packets on my local network, the problem seems to only happen when uploading/transfering outside of my network. 

I really want to get my full .7 up--or at least a reasonably close number as the full .7 isn't really a reasonable expectation; however, i don't think that .35 is reasonable either when it is barely half of my .7.

All help is appreciated