Yes, he is incorrect.
Let's pretend you have a Universal comic that would grade 3.5 with no work done. Now, let's say you had a professional use conservation to seal tears, etc. It would no longer be a 3.5 - let's pretend it grades 4.5 after the work is done.
The same goes for restoration. You could take an 8.0 Universal up to a 9.4 Restored if you just needed color touch to fill in ink rub, color loss, etc. The grade is as the comic currently is. If you remove conservation and/or restoration, the grade will certainly be lower.
I think Tony S is confusing this situation with the general difference between Universal and Qualified. Qualified exists to tell the consumer, "what this book looks like without this particular large flaw that does not effect story".