NWEA was renormed in 2015, but last year most schools were using the 2011 norms. It could be a difference between the norms. But yes, she would have taken a new test this year and a 251 on 6+ is actually "higher" than a 251 on the 2-5 (no, this isn't what NWEA will tell you, but from our own experience, the next level test can have much harder questions, making the two versions a bit difficult to compare). Once a student is scoring in the range your daughter was on the 2-5 test, they should be bumped up to the next level test. This would appear to be what NWEA recommends in order to avoid flat or negative growth.
Actually, though, I would view that score as growth, since it is on the higher level test (she probably had to answer harder questions on the next level test).
