A single use license (single song license) pertains to one single edit. Each license covers one “sync,” or one edit of the song being synced to a motion picture. If a cut-down creates a new version or edit with a new sync, this is considered a separate project and will need its own license.
Lifts, however, are covered by one license. A lift is when a section of the video is “lifted out” of the project. This means that the project was not re-edited in any way and the music was not re-synced. An example of a lift would be placing the first 15 seconds of a video on social media - the video is identical to the original in the sync and the edit.
A subscription covers multiple cut downs since you are granted unlimited uses under a subscription. Just be sure to create a license for any cut-downs you decide to publish!