I too think that you need to get him tested using the WISC test (which seems to be the commonly used IQ test in the private schools in my area). There are several reasons that the IQ numbers could have dropped - student having a bad testing day, test not being comprehensive enough, the test itself not being engaging to the child, underlying issues relating to vision or hearing etc. You, as the parent have a better idea of whether the child is gifted or not from daily interactions and observations. So, I suggest that you should wait to see the results of another comprehensive IQ test before coming to any conclusions.
