There are rules about reviewing and declassifying information. The rules get applied at years 10, 15 and I can’t remember the longer ones from the date the material was generated. In the absence of special waivers the material gets declassified. And you can bet those 28 pages do get reviewed rather than slipping through the cracks.
As an aside, it’s these classification rules that are tripping up people trying to defend Hillary Clinton using the “it wasn’t classified at the time” defense. If the months and days on the dates don’t match exactly, and there aren’t precise 10 or 15 or whatever year differences you’re only seeing the date when the material was stamped classified, not when it actually became classified. Since classification is determined by the nature of the material, not when someone stamped it as such.
If that’s the structure then they got reviewed once and not declassified and the next review isn’t due for at least a year. In my FIL’s experience though nobody tended to be in a hurry to declassify anything, nobody really wants to be the guy to decide something OK to have in the public space. Remember too there’s lots of lifers in the government, folks who made mistakes that allowed 9-11 to happen (and might be called out in those pages) will probably still be working for the government through 2025 or so, and “requests” will make the rounds whenever there’s a review.