The way I prefer to do things is copy and paste the xml to the desktop, rename and then cut/paste back to Mach3 folder, doing it the way you did is just the same though.
Your macros will not be copied however, when you open the new profile a new macro folder will be created and the default macros will be put in there.
If you then go to the macro folder of the original profile, copy all macros, open new profiles macro folder and paste then next time you open that profile it will have all the macros that were in the original.
Hood