In the flashback, set six years ago, ten year old Maddie is clearly taller than ten year old Liv. Yet in Move-A-Rooney, Liv claimed she had always been taller than Maddie, even when they were children.
It was said in this episode that Liv was ten in this episode, but if she was in Hollywood for four years, she would have left when she was eleven. If Liv was ten, she would have been in Hollywood for five years, not four years.