That was confirmed in the fact file:
"Freedon Nadd studied avidly under Naga Sadow. Eventually, the apprentice became far more powerful than the teacher..."
-The Official Fact File #90
This isn't exactly concrete but implies some degree of parity:
"The spirits of powerful Sith Lords such as Marka Ragnos, Freedon Nadd, and Karness Muur..."
―Star Wars: The Old Republic Encyclopedia
On the former, it is important to note Freedon Nadd was growing constantly more powerful over the century of his rule on Onderon that followed his learning on Yavin IV:
As Nadd's power grew over more than 100 years of rule..."
―The Complete Star Wars Encyclopedia
I agree the latter isn't much however.
It isn't and never was, I accept responsibility for having used them in debates, I did not however create them. I also apologised for it two years ago, you clinging to that is just plain evidence of your obvious vilification of me.
Go ahead and reinforce everything I think of you Beni, totally not expected at all.