My son attends a school with block scheduling. As he has taken more advanced math & science classes, he has had different teachers each time. My son selected his Trig/Pre-Calc teacher from Spring 2012. He cuurently has this teacher for Physics & will have him later for AP Calc AB. This teacher currently has concerns that he has only observed my son for about 6 months and have to check 'Not Observed' on some areas. Is this a valid concern? Thanks for inputs.