I have been experimenting/setting up a new PC/DCS240 Command Station for our club(replacing on old Win XP tower) and a 12 year old DCS200 Command Station). As mentioned, only DT 402D/DT 500 throttles get assigned to slots above 120(and the DT 402D throttles need the R21 firmware upgrade.) I was able to upgrade the firmware in the built-in PR3, the DCS240, and a DT 402D(both the R21 throttle and RF24 communications firmware. The built-in interface updates firmware much faster than my old PR3 - Nice!
Wednesday morning I take the new Windows 10 PC and the DCS240 to the club for the swap. I also have a new UPS to protect the PC(we have lots of power outages in this rural area).
Jim