Heh, On second thought, take a look at "snap reserve -A". I'll bet the Aggr Snap Reserve is 0 on the original, and the 5% default on the new.
"snap reserve -A netapp_aggr2 0" will set it to zero, and you should see the space.
We're thankfully doing away with that default, and this shouldn't be a needed step going forward. It's only required for SyncMirror/MetroCluster.