New XB10 modem: not getting symmetrical 1GB up/down speed

I received an email about new symmetrical 1GB up/down speeds available in my neighborhood. Received a new XB10 modem. The download speed is OK, but upload is capped at 400-500mbps max. Not sure if my modem needs to be reprovisioned, my plan isn't set up correctly in the system or if my house isn't really ready for the new symmetrical speed.