Do no harm. If you have an existing volume and settings, Nimble is not going to change them unless we know that will help you and you confirm the change. You may have chosen that setting for a reason like round robin, we have chosen not to do that for you. I would bet support might have a script to allow you to change all volumes to PSP.
So is the NCM PLUGIN behaving as designed? I don't recall setting up the other 6 ESXi host manually to use "Nimble PSP Directed" but I have added a lot of volumes post installation OG the VMware VIB.
