Another comic that I read in a barbershop as a kid, Action 448 (June 1975) has the kind of cover that demands one read the story.
Maggin, Swan and Oskner do not disappoint with the story inside. Roy Raymond is featured, having recently been hired by WGBS.
Steve Lombard is stuck being the joker nobody believes, after he has a mysterious encounter with an ethereal “13th floor” in the Daily Planet building, despite there not being such a floor. But Roy, counting the levels from the outside, discovers that there is one.
Superman has a bit less time for this mystery, as he is occupied with some strange aliens who keep popping up. In fact, the two are directly related, as the 13th floor operates as the arrival point on Earth for an alien travel agency.