For macOS 10.10 and later only. This script will obtain a user-entered number of seconds (as integer or float) and either add it to the current Start Time or subtract it from the current Stop Time of the selected tracks.
You might also be interested in Reset Tracks Start-Stop.
Remember: the current Start Time and Stop Time will be added to or subtracted from.
Perhaps Also of Interest...
downloaded 1h 17m 55s ago
Applet assists with swapping, copying, appending data between track tags
downloaded 1h 18m 12s ago
Export album artwork as folder.jpg to Album folder
downloaded 1h 21m 36s ago
Edit artist/composer-related tags text for sorting purposes
downloaded 1h 40m 12s ago
Display, create text file listing info of dead tracks
downloaded 1h 47m 56s ago
Create a .zip archive of the files of selected tracks
downloaded 2h 1m 36s ago
Three scripts assist with editing Work and Movement tags