You can read about PIE/PIF scanning in this article:
Home PI/PIF scanning - Who to believe?
An in-depth discussion about scanning, PIE, PIF, Jitter etc. can be found in this thread:
Read first: Precision, accuracy, and reliability of disc quality (PI/PO/jitter) tests
We also have an entire subforum dedicated to discussion about disc testing methods and software:
Media Testing/Identifying Software
Now for the specifics of your scans...
It really would help if you attach a screenshot of the scan instead of just the numbers.
Your Optiarc drive while capable of scanning DVD media does not report PIE correctly (it reports bytes in error instead of rows in error, i.e. it reports a number that is too high). It's still unclear how reliable it is for scanning, apart from the overreporting of PIE.
Your Optiarc drive can also report PIF per 8 ECC blocks or per 1 ECC block depending on how the Advanced scanning options are set in CDSpeed. By default it will report per 8 ECC blocks, which is not directly comparable to the scanning standards and to other scanning drives such as LiteOn DVD burners. I suggest you change the setting to 1 ECC for future scans (also in Advanced options).
A total of 367 PIF and a maximum of 6 PIF per 8 ECC blocks is a very good result, while a maximum of 6 PIF per 1 ECC block would be out-of-spec.
The applicable ECMA standards say that the maximum PIF should be no higher than 4 per 1 ECC block. There is no standard for PIF per 8 ECC blocks, but a very rough rule of thumb would be no higher than 12 PIF per 8 ECC blocks.
A maximum of 127 PIE per 8 ECC blocks is within specs (280 or lower) and is acceptable, especially since the Optiarc drives overreport PIE. I wouldn't consider it a good result, however.
I consider the ScanDisc C1/C2-PI/PO scan a waste of time and suggest you use a ScanDisc Read test instead, or even better perform a Read Transfer Test (a.k.a. Transfer Rate Test - TRT) on the benchmark tab, and look for a smooth read graph with no major dips.
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