Help with an Action

My situation is probably quite rare and complex, so I'll explain it in detail.

Many years ago, I put together a hand-selected collection of MP3s, which ended up taking a month or so and is now at 8000 songs. All of these songs were manually ID3 tagged, which took me forever. Unfortunately, I had a strange tagging philosophy. For songs that featured multiple artists, I would put the features in the Artist field, rather than the Title field. Here's what I mean:

What I have:

What every normal person has:

Can anyone tell me how to set up an Action to fix this? Basically, I want to batch handle my MP3s so that if "(ft. *)" is found in the Artist field, it is removed and instead appended to the end of the Title field. Possible?

See /t/11096/1
to move featuring from artist to title

I used this exact one, changing "feat" to "ft" (to match my tags), and the results came up empty:

Read there ...
Move "Featuring" from Artist to Title
Applying a proper filter expression can help to reduce the view and the work to the files in question.
If you follow the advices, then you should have success.

What tag-type do you actually read from the files?
What tag-type do you actually write to the files?
Make sure, that you read and write to the same tag-type.