Hi DrageMester !!! Thank you for your reply.
Guess what ? I suspected heat to cause this also since my CPU is still P4 and my case obviously doesn't have the best airflow. So being an obssesive-compulsive with test results, I'm still not satisfied with the 1st scan even though it's 96.93% because it's not all green (as you can see from the screenshot it has yellows).
Which prompted me to do the 2nd scan but this time I let the drive hangs out of the case (with proper support of course so it wouldn't fall off) and let the air conditioner do its magic. I can feel with my finger that the DRU is cool but to my surprise, the test result is WORSE.
And this doesn't explain also why I had good results (98%-99% quality ratings) previously with the drive properly seated in the case.
Now that you mention this, what would cause a drive to overheat other than bad airflow ???
I do have problem with this DRU where sometimes it wouldn't recognize discs. I'm a little bit of DIY person so I disassembled the drive to observe what went wrong. I troubleshooted this and I think I found what caused it. I think it's because of the tray mechanism motor losing its rotating power so when the tray closes, the motor's power isn't enough to have the mechanism make the laser rail part goes fully up (maybe this is what you called clamping mechanism). So what I did is whenever the tray closes, I would give it a push so the laser rail part fully goes up. When it does go fully up, the drive would recognize the disc.
Now that you mentioned this, what would cause the disc to not optimally clamped ??? Is it because of the motor like I said or something else ???
What's your solution to make sure you won't have variance anymore with your Lite-On scans due to overheating ???
Thank you very much for you insights !!! I really appreciate it.