I recently went through the Phuket one week sandbox and returned to Pattaya 10 days ago. I am here on a retirement extension and suddenly it occured to me that I might still be required to go to Jomtien and do the address reporting.

Is that still required? Also, will my 3 months reporting be required 3 months after my recent return to Thailand or must I go by the date given to me before leaving?

A TM30 report is not required now unless you change your address or enter on a new visa (new rules in June of last year).

Your first 90 day report is due 90 days for the day you entered the country.