woobi, those are very poor results for Taiyo Yuden media, even though I believe the earlier LiteOn drive such as yours prefer DVD+R media over DVD-R media.
You could try upgrading your firmware to the newest official firmware VS0M, or the unofficial Quality-patched 832S firmware CG5J.
The PIE levels should not be higher than 280 and the PIF levels should not be higher than 4 (except perhaps for a few single spikes), so your scans are way out of specs.
It's possible that your drive isn't scanning those discs reliably, but since the LiteOn DVD drives are susually very good readers, it's possible to have have a disc with out-of-spec PIE/PIF that reads flawlessly in the LiteOn but is unreadable in some other drives.
If you have another drive to scan or perform Read Transfer tests in, that would give you more of an idea whether you should believe the poor quality scans or not.