I'm at version 1.5.6 and I decided to go from a text custom column to a comma delimited cc. I delete the existing column and add the new comma delimited column. I import from my kindle.
Now I figure I've got to go through my cc field and change all the commas to something like an underscore or whatever. Typically the commas are there for authorLastname, authorFirstName.
I look at the contents of my custom column and I see that I've got semi colons wherever I expected a comma. On the rare occurrence where I've got a book in two collections, I see them both in the cc, separated by a comma. Meaning I can use the comma to put a book in more than one collection.
I then look in the update history and see Meme has saved me a bunch of work. To make it sweeter, I will still have commas in my collections on the Kindle.
Excuse the expression, but this last update is slicker than snot

Way to go Meme.