May have different content. Same name doesn’t mean same content. This includes file length and type. If you’re having trouble figuring out why Gemini hasn’t removed a duplicate file from you iTunes, the answer is quite simple: it’s probably not a duplicate. Yes, we know that the files may have the same name or be the same song, but there is probably a difference in content.
When Gemini scans, it looks at the content of each music file, not the similarities between the file(s). The difference in size, length, name, etc., between two (or more) songs means that the content in each file is different. It may be the same song, but because the two files are different in content, the files are not considered duplicates. This is why Gemini will not remove duplicates from your Mac: they aren’t technically duplicates!