Have similar filenames, but not being returned as duplicates

[Cara]

I'm attaching a side-by-side of 2 folder structures that I'm comparing.

Folder on the left contains "All Contacts.vcf"
Folder on the right contains "All Contacts (2).vcf"

I have tried all manner of the "Find similar file names" options and none of them return these as duplicates.

The 2 files have the same mod date and size.

I would hope that AllDup would also search the subfolders on the right, one of which contacts a file with the EXACT same name.

What am I doing wrong?

[Cara]

Today, searching a single folder (using "Compare only files within the same source folder," on the Source Folders tab, and I *know* that I have 2 jpg files (one's extension is upper case, the other is lower - does that matter?) that are the same date and size. My search method is "Find Duplicate Files on the Basis of their Properties," and extension, size and content are selected. AllDup is NOT identifying these as duplicate. I checked file and folder filters and they're both turned OFF (this has been a problem for me in the past).

What do I need to change/reset/set to get this to recognize duplicates as duplicates?