I’m not a pro, but I think your scan looks pretty good.
What’s the media ID of that Ricoh disk? Is it +R or -R?
Unique Disc Identifier : [DVD+RW:RICOHJPN-W11-01]
Disc Type : [DVD+RW]
Manufacturer ID : [RICOHJPN]
Media Type ID : [W11]
Product Revision : 
Disc Application Code : [General Purpose]
Recording Speeds : [2.4x - 4x]
Blank Disc Capacity : [Not Supported By Method 2]
[DVD Identifier - http://DVD.Identifier.CDfreaks.com]
For the first write ok. I’ve read that the current Ricoh 4x +RW aren’t very durable. Can you rewrite them a few times and do an scan after every rewrite? Normally PI/PO should go up. You can rewrite them partially too. I bet you’ll see the individual rewrites.