To answer your question mp3tag cannot do what you want or scripts because they can only parse one page at a time. It's would make life that little bit easier but not critical IMO.
- First load all your single tracks into mp3tag tag. (You can deal with albums etc later)
- Starting at the top tag a single track with for example the 'Beatport by &stevehero v4.0#SINGLE TRACK Search by (Album)Artist + Title.src'
- Hit the down arrow
- Hit Ctrl+I (This repeats the same script you ran earlier)
- That's it. You're presented with the search dialog with two clicks extra as opposed to one with the functionality you described.
Hope this helps.