Quote:
I think that thing that looks like an "S" is too close to the tail to be a mint mark. My guess is they also felt it was a 1928, but the illegible date notation was because they couldn't determine whether it was a 1928-P or 1928-S.
Comparing the PCGS images for
1922-S and
1928-S, the mint mark on the OP coin matches the 1922-S -- the 1928-S is much higher as you indicate, but all three images for 1922-S have this lower position.
That said, we recognize that mint marks were hand-punched at the time and variations can occur so even this may not be conclusive. But it still looks like an "S" mint mark to me rather than convenient-looking damage.