Beyond the classroom teacher, the entire climate and atmosphere of each school can vary widely, as can the personality of a particular grade level within a school. In some instances, despite all things (behavior) being equal, the way different teachers or schools perceive and respond to the gifted child may differ so much as to cause the same student to acquire labels ranging from PIA to exemplary student . -My son experienced this metamorphous after switching schools two years ago.
Your son sounds gifted (and fortunate).