IsoBuster needs to be set to 'local file stamp' (in Options > File System settings)
Using that method, all the dates match. I had the feeling that I was doing something wrong.
Speaking of doing things wrong, I have a question about the fields in the PSX database, as we don't seem to have a guide that covers them all.
For the "EDC" field, I've noticed that one of my dumps contains the line "[INFO] Number of sector(s) where while user data does match the expected ECC/EDC there is no EDC: 23456" in the "_edcecc.txt" file. Should "EDC" be "No" for such discs?