In stats board / civil service etc, a convesion of scheme (eg from mss to mx) is considered to be a hassle. Needs approval from your head etc, paperwork to be done. I presume that your cuurent position is one of the those support work type, one which the hr is only matching to those of a mss scheme (aka poly dip holders). Therefore, it is unlikely you will be converted even you go for a masters or local Udegree. Options :

Exit and come back if you really like civil servant job
Ask for a transfer of appointment, one to that which needs a MX scheme as stated in the job description.