LG 4163B Read Error Correction vs LiteOn 166S

I’m trying to read a dammaged DVD.
I get unrecoverable errors on both my LG 4163 burner and my Lite-ON 166S DVD-ROM. The interesting part is that read errors are at different places when read with the two drives. Anyone have good explanation why the difference? Is the error correction different or some other difference causing that?

With the LG 4163 generate over 1000 error sectors all concentrated at the 30% mark.
With the Lite-On 166S only about 70 error sectors at 16% and 60% mark (none at 30% mark).

From reviews on the web I was under the impression that the LG 4163 has good error correction capabilites but seems it isn’t doing too good compared to the 166S.

Different drives read discs back better than others, always lowering the read speed with something like Nero Drivespeed may work better, lower read speeds result in less errors usually.

I have found that the Liteon drives read back scratched discs very well, they can read back some really crappy discs.