Regarding civil services age relaxation to ex servicemen

In its notifications upsc says that age relaxation won't be applicable to ex servicemen those who asked discharge on his own request. First what this his own request mean here Will it be applicable on a person who is ex servicemen and gets selected some where and asked discharge and then applies for civil services with age relaxation. Here the case is of air force personnel whose engagement is for 20 year but he earns his pension after 15th year and can be called as ex servicemen but cant be relieved before 20th year until he got select in any class A/B services. Will this age relaxation be applicable to him Don't you think it's a disparity between services where a person served in navy or army can seek age relaxation as their initial engagement is for 15 years. But benefits of ex servicemen can't be availed by air force personnel just because of this term his own request. Because after 20 years he won't be eligible to apply as even after age relaxation his age will be over 37 years.