It's unfortunate how little you know and how obvious it is. Though LTE IS LTE.., that doesn't mean any LTE device can be activated on your ACCOUNT with the other carrier. Your VZW account doesn''t know what the ATT LTE device is because it IS a different device. Look at the model differences between the HTC ONE Verizon just got and the other carriers. Verizon devices usually work on other carriers but it's not a mutual relationship. Do more research.