In Group A competitions, B-graded players must attain a minimum of 2 pts and A-graded players must achieved 4 points out of a total match of 9 matches. So to said, players when decided to participate in the annual match will have to try his or her best to achieve the min. points to continue carrying his 'Grade'.
If a B-graded player fails to gain 2pts in the last 2 years of participation, it will be wiser or more compatible for him to play in Group B games when chances are better and skills are more comparable. For A-graded players, failure to achieve the points will be demoted to Grade B. If next 2 years continue to achieve 2 pts, he will play in the Group B.
This can perhaps keep the chess standard of Sg, making matches more competitive and title-holders more current.
Just expressing my personal opinion. No offence to anyone or organisation!