Meh, a lot of Disney artists don't consider Disney albums proper albums. Like Miley doesn't consider anything pre-Can't Be Tamed part of her discography (minus Party In The USA).
She only ever performs songs from Can't Be Tamed onwards.
Maybe she just means fourth because they were from her Disney days like the other member said, a lot of Disney stars don't count their Disney albums as their work because they probably had little to no say in the music
Unbroken probably felt like the first time she had control over the music so that's probably why? Idk