She probably not including songs like BLUE BIRD for AT because as I observed her, she likes to keep songs like that and July 1st for a-nation and maybe thinks that "Oh well I'm going to perform those summery songs at a-nation this year so need to sing it on AT" idk
Nonethelesss, regarding A BEST 3, imo the public see the vote as an opportunity to pick their favorite songs to be performed regardless of the occassion or the A BEST LIVE title because she had many underperformed/non performed songs so I guess it's a great chance to 'shove' it in her face what the fans wanted. Besides A BEST 3 wouldn't really need a vote, ayu and avex can decide it and we could probably know how the tracklist will look like.