As you requested, I created a local account under my administrator account, rebooted, and logged in as that local user.  It did not have any affect on the download speed/bandwidth, either via wi-fi or over ethernet.
I still don't understand why my Surface Pro download is only half of my much older XPS's.  I just got a new Linksys modem for my home today.  XPS speed test results - 155 Mbps.  Immediately then tested the MSP6 - same service provider, same wi-fi network, same band, same channel - 68 Mbps.  Less than half...