During recent testing I burned a DVD and ran a scan (1) which gave satisfactory results. Then scanned for quality (2) again not much to complain about.
Then I created a error correction image (3) notice the reduction in speed just at the end. when viewing the actual program there is a good deal of visual corruption both on the original and on the copy.
I have run other DVDs through this and found no drop off at the end.
My thoughts are:
DVD speed seems to be saying I copied what you gave me and the result is fine.
Dvdisaster seems to be saying I copied what you gave me and by the way its pretty crappy at the end ?