Support helped me with this.
This is what support suggested:
Thanks for the request.
First you can have several installation on the same PC.
In your case you can have the DSC V8.2.3 and DSC V8.3 installed.
There is only one restriction: install them on separate folder.
Can you check if the USBtap is correctly installed and recognized ?
Plug the USBTap on the PC, launch the CCS and type:
show com
delete all
show cc
config cc utap
show wdv
show cc
Basically the problem was the "config cc utap" is what fixed everything to work. Don't forget to save the config after you do this.
Thanks support!