Don't expect official lte support for this device. The reason it even supports the aws band is because the s4 pro chip contains the radio for it. However the device is missing other hardware like the amplifier, and what not. Google/LG didn't think that it would work well enough without this hardware and thus when they filed the necessary paper with the FCC to gain certification, it was left off. So therefore the device isn't officially certified for lte usage.
After the device was released, and hackers found a way to enable it, Google protected itself by sending out a radio in the 4.2.2 update that would permanently disable lte usage. Obviously since it's a nexus is easy to undo this, but the message was clear after that. Unless this phones gets refiled with the FCC, Google will not officially support lte with this device.