I guess I started this Marvel chipping discussion - sorry!!! (especially since this is an AF15 string)
For what it's worth, I always felt there is a little mystery about how the marvel chipping actually occurred - clearly there were dull blades involved, but the very strange way that the tears happened (more like cracks in the paper than tears), and it is also strange that sometimes the "cracked" paper stays in place even though the tear goes edge to edge - I figure that in addition to dull blades that it might also have something to do with the way the ink dried after or before the cut was made. I also wonder if there was an abnormal amount of pressure being applied to the edge of some covers but not others somehow.
Maybe this has been addressed in the past (or under a different subject), but I would be curious if someone with old-time printer knowledge could explain why the cracks happened the way they do.
I certainly try to avoid Marvel chipped books when possible, but I knew I could only afford a 7.5 at the time and my flaws of choice were Marvel chips and dust shadow. I also did not really care so much about the CGC grade (although that clearly affected the price) - I kind of liked the idea that the main flaw happened during manufacturing instead of handling. Every copy of the 35 cent Amazing Spider-man #171 has a nick in the spine about four inches down - I would never want to buy a 1970's book with a nick in the spine, but now that I know that it happened in manufacturing and they all have it, the nick does not bother me as much - that is kind of how I feel about Marvel chips, albeit I know that not all copies were inflicted!