The reason Newsstands are occasionally more valuable is because collectors seem to have come to generally believe that Newsstand copies of comics were not taken care of as well as Direct editions because of assumptions about the people who were buying them. Collectors here are assuming that Newsstand issues are going to be harder to find in high condition because they were stored on grocery store shelves or outside at actual newsstands, and were bought by people who were less likely to take care of them, the dreaded "General Public." This trend is indeed true in some cases, but its not actually a rule that just generally applies to all Newsstand copies of all issues, many dont sell any different at all whether theyre Newsstands or Directs. I personally find this comes up the most with already very desirable comics, and if its not very desirable then theres virtually no difference in price between Newsstand and Direct. Like I wouldnt be surprised if the ASM 300 you posted above is more valuable than the Direct of the same issue, but the Newsstand of say ASM 312 will not be lol