2009-S Proof Lincoln Cents

Six years later I found the explanation the mint put out with some of the 2009S cent issues. Since the Mint admits the issue, would it not be considered a variety/error? I have 5 of these sets with excessive "silvering/toning" to where it looks like exposed zinc. When it's all said and done, I'll have 10 of these sets, all $20 or less. I do like the dual coloring which appears mostly on the reverse but also has affected the obverse on all my sets. I live in Florida, under A/C and only my original 2009S SMS has no toning. I don't think this is a care issue from anywhere in the country but consider it a mint issues that belongs to the responsivity of the mint.

I can't make an assumption if the notice was directed for all mintmarks, but I default just to the S mintmark since it's the only one that seems to have the only conversation about this 'magical' toning.

On another note: is PCGS still grading these S mint sets as a group (I bought one years ago as PR69)? If so, do they charge for 4 coins or just the set of 4 as one?