What Jamos said above is correct. Notice on the first scan (the LiteOn one) that the PI Failures above 4 have a red background. Below 4 the color is green. That's because on a LiteOn the max PI Failure is 4 for the "safe area". Once a LiteOn gets above 4, then it's going into "dangerous" territory regarding a potential playback problem.
With your second scan (the BenQ one) the PI Failures show all green in the background. That's because your PIFs never got past this "safe" area. On the BenQ, the PI Failures "danger" area doesn't start until 16 PIFs. If you had PIFs of 16 or higher, you would have seen a red colored background on your BenQ scan in the PIF area just like the red background on your LiteOn scan.
There's a 1:4 ratio between the LiteOn and the BenQ PI Failures. That is to say, a PIF value of 1 on the LiteOn equals a PIF value of 4 on the BenQ. A PIF value of 2 on the LiteOn corresponds to a PIF value of 8 on the BenQ, etc. Since your max PIF value reported in your LiteOn scan was a 7, that would be like getting a max PIF value of 28 on your BenQ. That's why your LiteOn scan is in fact of worse quality than your BenQ scan. The max PIF value of your BenQ scan was a 7 which would be like getting a max PIF value of 7/4 on your LiteOn (7/4=1.75, a little under 2). Do you now understand this?
Jamos explained it correctly when he said, "The benq scans at 8ecc so the pif limit is 16 not 4". Whatever max PIF value you get with your LiteOn, multiply it by 4 to get a corresponding BenQ equivalent value. Likewise, whatever max PIF value you get on your BenQ divide it by 4 to get a corresponding LiteOn equivalent value. PI Failures are much worse than PI Errors regarding causes of skips, jumps, or unreadable discs. That's why Nero CD-DVD Speed uses that factor so highly in determining the quality score of a given scan.
I was tempted to say the reason your scan got a higher quality score in your BenQ drive than in the LiteOn, was because the LiteOn scan was of a NEC 3500 burn and not a BenQ DW1620 burn.
All joking aside, you obviously know that if you want to compare a NEC vs. BenQ burn you have to do the following: Test the exact same movie burned on exact same media type (one in the BenQ and one in the NEC), then scan both burns on the same drive (either the LiteOn or the BenQ, but not both) and do both scans at the same scan speed. Anyhow, I hope this helps you out.