As I know you are not eligible for PG scale as your M.C.A. degree was not considered by the SSC as relevant to your post. Recently SSC has started considering M.C.A. degree as relevant for schools where computer science is taught.
@saij
He has already informed that he is a B.Sc (Hons.) in Maths. M.C.A. course cannot be pursued by a candidate unless he has already acquired B.Sc. degree. It is NOT necessary that his B.Sc. degree should be related to Maths only. Candidates with Graduate Degree in any discipline (3 yrs course) with Maths in 10+2 level are also eligible for admission in M.C.A. course.