One scan is missing, and it's difficult to interpret simple numbers from the stats.
About the first disc, you kept it in a DVD binder... and the media is printable... most probably the dreaded humidity problem. Let this disc rest in an open jewel case for an hour or two and re-scan it. I bet the result will look different.
Besides, binders can easily lead to scratches. Don't get cheap with DVDRs, they're not as sturdy as CDRs. Offer them proper storing (DVD-style cases), store these cases vertically, and you'll avoid many, many problems.
BTW you don't put sticky labels on these discs, do you?
About the second disc (in a spindle), no clue. All I can tell you is that media degrading this fast is almost impossible, unless it's been physically damaged, or warped.
I keep reading this here and there, but I have a hard time believing this as I never, ever experienced this. I scan everything just after the burn, and consecutive scans were never different (except for fast degrading discs like Ritek G05/G04). A myth if you ask me, but YMMV of course.