So, this media you've shown scans of is essentially 2 year old media? Possibly, that's the problem?
Your 2nd scan (July 2003) is not a hall of fame achievement, but good enough for cheap media, I suppose. Still, it's a 95. Considering the media is now 2 years old and the media you're using is not very common (esp. if it's 1x stuff), so there's no telling how well the media 'ages' even without data written on them. Others have mentioned data integrity (and in this case, media integrity) is greatly influenced by the storage methods & conditions. Care to comment on how they've been kept over the last 2 years?
The funny part is ... comparing the 2 scans ... your PIE's (max & ttls) actually DECREASED!! Lol.