OK. I just tried an experiment.

I de-listed one of our BIN items and then re-listed it.

I found the option to enable Fast and FREE so I selected it. This is the only change I made to the listing.

When I tried to list the item I got a RED error message.

Said something like "you must offer an overnight delivery option to choose this".

I thought offering Express mail as an "overnight" option would qualify but apparently not.

So I just re-listed as it was.

*** FAIL ***