Bob, you posted your comment while I was responding to Pete's post.
But, you bring up a separate issue - a re-measure of an expiring course, and accepting one ride, if that ride is withing .08% of the original measured length.
Gene, should this discussion be moved to its own topic? Very appropriate discussion, but not directly related to course modifications .
For what it's worth, I would entertain a discussion of single-ride measurements of unchanged courses, to allow for a new 10-year cert. At this moment, I would favor such treatment for Half-marathon or longer courses, where traffic is a safety factor.