Out of the box the newest MPVI3 won't allow some emissions parameters to change. They didn't tell me about additional training required to do these changes. I learned about it on the LS1 tech forum.
Here is a link to the YouTube video HP Tuners put out.
https://www.youtube.com/watch?v=Ma0CkdnDkrw&t=4s
in VCM editor, from the help tab, select Parameter Access. There is a link to the training. Follow his directions to get your access code. Once all that was done I had shut my laptop down & restart it before I gained full access to change the parameters.
Hope this helps...