I've realized that this feature isn't so accurate as I think. I've tried it several times with my project, and only 2 from 10 times of trying were resulting the real same spritesheet object composition.
Why do I need this feature
=> I want to reducing the spritesheet object composition, so the less of duplicated object, would be make the game size smaller.
What it is for?
=> I don't really want to rely on Construct official images compression feature, because they only cut around 3MB, from actual total 13MB images size. I use Tinypng that can cut from 13MB into just 3MB! doesn't it more amazing?
What's the problem?
=> Each time I export the files to Cordova, and then I tick the Deduplicate features, I always need to compress them manually every time. Eventough I'm not touching or editing any sprite, tiled background, and all of them.
It's really bother me as I think that "Deduplicate feature" could help me alot for its function, but something seems wrong with it. Hopefully 
Ashley or somebody can help me to explain nor trying to enhance how this deduplicate feature work because actually it's a very wonderful feature.
Thank you!