I am new to BB and a little confused by the "Song Form" dialog box. I guess this is important for the playback of the song correct?

I am aware that a chorus is once through the whole form of the song. So here is my issue...

Let's say I have a simple song that has two sections: A verse section that I would call the "A" section, and a refrain section I would call the "B" section.

If the song begins with two verses followed by one refrain then finally ending with one more verse then shouldn't the form of the song be: A-A-B-A??

The problem I'm having with the Song Form dialog is that I have to call the first two verses A then the refrain B then the last verse C. That makes it A-B-C instead of A-A-B-A

Also, I let BB generate a intro. Is that supposed to be in the song form dialog? I tried to put it in as A but then BB gave me error messages that my sections were not ending on the right measures??? Does the intro belong or need to be in the Song Form dialog box??