Photoshop Elements 12 (photo editor) and Premiere Elements 12 (video editor) are standalone program, each with the Elements Organizer 12. When these programs are on the same computer, they share the same Elements Organizer catalog. All that being said, since your issue is with Elements Organizer and it identification "Duplicate Photos" not videos,
I would suggest that you might repost your thread in the Adobe Photoshop Elements Forum for a boarder perspective on your situation.from people such as Barbara Brundage, MichelBParis, et al.
The following is an example of what I mean about the Adobe Photoshop Elements Forum and this type of question.
Please let us know the outcome when you get a chance.
OK Thank you
I am not sure what happened. My post numbered 1 is missing some information that I was sure that I had included.
I had written that tonight I looked a definite bunch of duplicated photos in Elements Organizer 10 and 12 and found no difference in the results from the Photo Finder feature. The duplicates were spotted right on. But, I have yet to put the feature through a challenge of sorting through real duplicated photos and similar photos and non related photos to pull out the real duplicated photos.
I believe that the Adobe Photoshop Elements Forum group will be able to give you the most immediate best possible answers on this.