All good stuff.
I have mixed feelings about all of the above and I think it boils down to integrity.
Some thoughts:
There are many of us who not only measure the course(s) but also work at the races run on them. For those races run on these courses where the measurer has been out there every year since the course was certified, I say just submit a new Certificate with the old map. No additional measurements are necessary unless of course the measurer thinks there was a change. Any new notations due to changes in landmarks would be noted in an updated map.
If the original measurer HAS NOT been involved but is very familiar with the roads (hometown - traveled on them daily), then I say apply the above.
If the orginal measurer HAS NOT been involved and is not familiar with the area, then I think a single measurement should be required and new Cert and Map submitted.
If a new measurer (different then the original) is measuring the course for renewal, then I think that a single measurement is required unless it is greater then 0.08%. The two measurements should be required.
I have had situations where I went out to remeasure I course that I worked on over 15 years ago. I was sure that the roads were the same but I got a significant difference (40+ meters). I measured the course several more times - always coming up with the same difference. I was going nuts! I called my buddy Jim G. to come over to Long Island (Visa required) and fortunately he confirmed my measurement. After I contacted DOT and found out that a long stretch of the course (service road of the Long Island Expressway) had been altered about 10 years ago!
Just today, I went out to remeasure a 5k course that has expired. It was measured by another measurer who is no longer in the business. My measurement was 4 meters longer then the original! So, thinking we do I screw up, I measured it again, then again (total of 3 times) all measurements within a meter or two of each other.
Why bother?
There are several talented age group runners around here, I we owe it to them to get it right.