Why cgpa to percentage varry from. University to university.??...why some university deduct 0.75, some deduct 0.5, some multiple of 9.5, ??which is mostly affect to apply government job who need...

May I know why cgpa to percentage formula vary from university to university... Which factor affect..plz reply...PSU job ask 60%. Some university deduct 0.75, some 0.5, some multiple 9.5..University which...