It does make you think of the difference between comic time and real time --and by extension it makes you think about the ludicrous nature of the Superman universe and the Supermanica itself --kind of fun really.
I think the "Fleisher method" of including dates in the actual plot synopsis is simply a way to break up the monotony of a long entry and the monotony of having every single citation read exactly the same (you get to leave the date out of the parenthetical citation if you mention it in the main text. It's just a way to shake things up stylistically. Another method is to introduce a plot synopsis by using the old reliable "In Action Comics #345 ..." gambit. Not a rigid rule but a useful tool (hey, that rhymes!).
I'm starting to think I must have a sickness of some sort as once upon a time I would have imagined discussing encyclopedia style would be something akin to water-cooler talk around the accounting department.