CGPA system in Malaysia

Higher Education Institutions in Malaysia apply the system of CGPA in their grading. However, this system is not equally synchronized in all universities. Certain Universities have set their "A" grade to 85 marks, most IPTAs only required 80 or even 75 marks to obtain A. In the end, most students from IPTA tend to achieve better CGPA because of the lower grading set up. How is this possible?