Is it important for Diagnostic Assessment by the start of semester?

Yes it is important.  This will help the school and teacher  for selection of the student based on their  intelligence quotient (IQ)  to place them in a right level or section ( Secondary level ). Without it, school may find dilemma to give the right course to the students. And  this is use also to measure the student capability and determine what field of expertise he/ she may fit ( college level).