Im not editing the article regarding the numbering of the Fort Smith section of I because it seems the writer may have been there more recently  However IIRC when I traveled that road shortly after the newer part of I was completed a few years back the exit signs and mileposts WERE renumbered to be consistent with the new road ie from Oklahoma line north though local billboards still had the old exit numbers  Perhaps an AHTD resigning project erroneously restored the original exit numbers and mileposts