Almost. I did that. But then I also had to remove each sensor one at a time. Go to remove device, then start the removal sequence on the device, and it will show "removing unknown device". I did that for all of them, per tech support's instructions. Rebooted, added them back, and I'm good to go again.
Curious that wiping the device does not touch ZWAVE info. Nor do backups contain ZWAVE info as far as I can tell.