PUC is generally useless. Unless there are significant financial penalties levied against PPL, they have little incentive to resolve this quickly, if at all. Prospect that some may never get truly corrected bills. Has the grace period for not paying past due bills been extended beyond 3/31?

Other than the PUC, I don't know what recourse one really has other than posting on social media and persistently contacting PPL via phone, letter, etc. Litigation is expensive and likely requires binding arbitration (should be optional, but that's another topic entirely).

When comparing months, look at many billing days there were. Generally, it's around 30 plus or minus a few days. I suspect for some, one month is say 10 days and another 50 or some other random variation. For messed up bills, PPL needs to do more than just say trust us and pay the so-called corrected amount. They need to explain the situation better.