The IAS is the Iowa Acceleration Scale and it isn't actually a test that your child takes. It is essentially a likert scale that is filled out using prior testing information and subjective opinions of teachers and parents. If you want more info on the IAS from those of us whose kids have had it filled out on their behalf, let us know.

In regard to the WISC, both of my kids who've taken it did it in one session and also did achievement and other testing in the same session.

Study Strategies for Accelerated Learners