My most recent 1620 is same as yours and had B7S9 firmware. This firmware was only produced for China because it was tailored for the extremely poor media that was available there. For this reason, it gives reasonable quality scans on questionable blanks but doesn't do so well on quality media. If you want long term readability, you should upgrade the firmware and use high quality media only. If it means accepting slightly slower burns, it's still preferable to ending up with a pile of dvd's which cannot be read after 6 months. My best results with TY02, TYG02, TYG03 and MCC004's are with B7U9 and B7V9. Have stopped buying all Ritek blanks now as I've had so many spindles that I've had to return.