For us, filling it out "WITH" us, meant we filled in teh non-school numbers such as outside of school activities the child participated in etc. They did it while we were there, but the teacher's filled out what they thought without us there, but we went over it with them..
The IAS blank forms come in a pack of 10 and they wouldn't give us a complimentary one. The school purchased the blank ones for us. We did the same thing, filled it out ahead of time with our numbers, conservatively, so we had an idea what they might come up with. We were low compared to what they actually scored it as, which helped!
