Not really, the drive is slowing down to read the damaged area and when it sences its past it then it speeds up again till the next area. If you have Nero installed you can use Nero Drivespeed to limit the reading speed of the drive to 2x.
Scratches are not the be all and end all of a DVD’s errors, you also could have a problem with the die, improper writing quality from the orignal burner can also make a disc unreadable which can then be compounded by scratches etc. I have a few cheap DVD’s that I wrote that are in pristeen condition, no scratches or marks but I cant read them on the BenQ because the discs outer edge was not recorded correctly and has to many burning errors on it. No error correction will fix that error so I have to re-copy them from the originals & re-shrink.