That is how the school handled testing my son, but not the private neuropsych. She did it all in one day, with a few breaks thrown in. The school did it in short sessions over the course of 2 weeks. However, for my son, the scores were very close (one was the Weschler, the other was the Kaufman), so I would consider both valid. I can see how easily the disruption could effect the child though.

~amy