It's working ok for me.
I got into Platinum, then edited something in my Master.ins, which for me, is located at
c:\Users\Tom Parker\AppData\Roaming\Cakewalk\SONAR Platinum\Master.ins
then hit the Reset button, and I immediately saw the change.
I then undid the change in Master.ins, hit Reset, and again saw the change.
I know there are several different Master.ins files around, are you sure you're editing the one in AppData\Roaming ?