Yes, installed latest GS-911 software and firmware. Yes, using Windows based laptop computer and the GS-911 app with the USB cable connected. Yes, followed proper procedure for hooking up. Otherwise wouldn't have been able to Autoscan, see everything and control everything. Well, except the TPMS ECU.
Yes, I'd read about BMW switching TPMS manufacturers from Schrader to LDL Technologies. But my understanding is that referred to the TPMS Sensors in the factory rims, not the TPMS ECU. I wouldn't expect different sensors to prevent the GS-911 from seeing and communicating with the TPMS ECU itself.
Got response back from BMW Dealer saying that locking or unlocking the TPMS ECU isn't possible with the dealer's BMW service computer. So, I recon it's time indeed to submit a troublecall to Hexcode.