I’d stay away from such an old drive and buy a newer LiteOn instead. The newer LiteOns support Jitter scanning and the 1633S does not.
Firmware updates sometimes change reading and thus scanning behaviour. I have seen it happen on two different LiteOn drive models, both of which were poor readers with initial firmware and got better with a firmware upgrade - this also affected scanning and the reported PIE/PIF decreased after the firmware upgrade.
IMO it’s irrelevant to use the term “accuracy” for quality scanning - the drive reports what it experiences, so the PIE/PIF/Jitter values are essentially subjective. There are some drives that misreport what they experience, however, and such drives can be considered inaccurate, buggy, faulty or whatever you like to call it.
@[B]rottenapple[/B]: Welcome to CDFreaks!