Ah, I was under a different (wrong?) impression.
If you look at the following example chart from Audiodev's pages (it shows an example results of a DVD scan): http://www.audiodev.com/default.asp?GROUPID=200336141121681
It shows a finer scanning interval accuracy than the results you show. That is why I was intrigued why this was so and I mistakenly thought it was due to a different scanning drive/software.
But apparently it's a setting defined by the scanning operator who can define less scanning points to speed up the scanning process?
Thanks again for all the clarifications and feedback, I'm learning a lot from your efforts!