I also don't agree that AC should move PY clients to Y to accomodate clients who were dowgraded from J.
For me , the biggest issue is tha being SE and 75k would lead one to believe that you would be further down the pecking order of those being downgraded. that's the issue
Your approach results in all but two of the J pax ending up in Y. I don't even think SE is enough to save you if you want to keep PY pax in PY.