Is cas-4 mandatory ?

pdgoenka (Dy Mgr) (123 Points)

11 March 2017  
Two different manufacturing unit (Pvt Ltd ) with different excise registration but same set of directors. Both these companies buy each other's semi finished goods and finished goods for onward sale. For determination of value, is it mandatory by excise rules to get CAS-4 certificate from ICWAI certified accountant for every financial year ? In case certification is not done, then what are the implications ?