It seems that someone behind the scenes couldn't make up their minds as to the main character's name. It changes from Hinkley to Hanley, as noticed for the first time here, then back to Hinkley several times during the run of the series. The first time this is actually voiced is in "Reseda Rose" when Rhonda calls him Mr. Hanley on multiple occasions. His name continues to change back and forth from season 2 onward.
The reason behind the switch of Ralph's last name from 'Hinkley' to 'Hanley' (later to resort back to 'Hinkley') was due to the assassination attempt on President Ronald Reagan by John Hinkley, Jr. in March of 1981 after production on the first season began.