I have the problem:
An MCC-003-00 disc shows a strong change in asymetry at around 350 MB, and exactly there it has a severe read speed reduction in the Toshiba drive (PR off this time!)
It is known that Toshiba readers are very bad at reading badly written weak sectors on CDs, which is nothing else than bad asymetry. So this problem with Toshiba drives seems to be there for DVDs as well
When power rec kicks in, it seems that the change in the asymetry makes the Toshiba drive fail to read that area.
Too bad this can't be the only problem, as I don't see such a change in asymetrie in the taiyo yuden disc that doesn't work