I'm also a Newbie . First of all, I want to thank you, too. Please keep the good work up! I'm a big fan of it!
Since, you are using LiteOn Drives to verify the DVD+R DLs, i wanted to contribute some lines of an article about DL which was published in the latest issue of the C't Magazine in Germany. They tested the new Philips DVDR885P and verified the outcome:
"Although the DVD+R DL gets good grades in professional measurments, some drives have difficulties to read the second layer correct. This occurs not only in LiteOn Drives, but also in some drives from Phillips, BenQ, Pioneer"
Hi Kita and welcome to our forum! What CT found, have been already confirmed from our test results, the mentioned drives can make perfect CD-DVD graphs but the reported error rate is just..enormous. Maybe we shouldn't expect much from DL scanning and more focus at the compatibility part...
From our side, we are doing our research and post the test results for all to read and comment.