The situation at your school sounds so familiar. Are you required to test those students with the very low IQs? We have to test ours, but they take a special test, not the regular mandated state test-- the TAKS.
Why are you bothering to give IQ tests to children with very low IQs. It is not as though a five or ten point difference on the S-B scale is going to make a difference. Why bother to have them in school in the first place?
Every public school is allowed to exempt 5% of the total population from whatever standardized test is used. There are only a few tests on the list--Stanford, Iowa, in Virginia, we are allowed to use the Standards of Learning. 5% may be exempted.