In this number with Maddie and Chloe her timing is off a lot because Maddie and Chloe have a different style to Nia. Maddie and Chloe are much more technical and elegant than Nia. However, when she does do a lyrical solo she executes it very well as she doesn't have to be at the same speed as Chloe and Maddie.
In this occasion she is dancing with less advanced dancers and the dance that they are doing is in her calibre. Nia is very good at acro but always drops a bit on the lyrical dances.
What I have learnt from watching Dance Moms is that if you forget your solo just improvise because it looks much better than what Paige did. However, when Paige knows her sold she performs extremely well. Paige is amazing.