It is very common to see songs being released individually as stand-alone singles before releasing a larger project that includes that same (previously released) song. This new larger release might be an album, or an EP. You may also notice that artists often release extended or deluxe versions of previously released albums that might include new bonus tracks.
If you have a single that was previously released, you can always include it in another larger release, as long as the *ISRC code is the same for that specific track. This way, you can re-release the track without having a duplicate, but you can also maintain your stream count!
If you have a deluxe version of a previously released album, you still have to tag it as a “New Release” when you are submitting to Trac. You would also input the correct ISRC codes for each respective track, with the exception of the new bonus tracks. You will get a new UPC assigned as well.
*ISRC (International Standard Recording Code): the international identification system for sound recordings and music video recordings. Each ISRC is a unique and permanent identifier for a specific recording, independent of the format on which it appears (CD, audio file, etc.) or the rights holders involved. Only one ISRC should be issued to a track, and an ISRC can never represent more than one unique recording. (Source: RIAA)