This whole grade A or grade B talk has no basis IMO.
It may very well be that TY sees a market for x4 discs that are still profitable for them. And they call it "value" because you are getting a great product for a low price - hence the "value" marketing speak.
The only way they are "inferior" to x8 and x16 discs is they take longer to burn and therefore have potentially less appeal and price point value.
I get great burns with these discs.