I called IMU Office and they told me that the purpose of calling 10 candidates per seat is to maintain waiting list of candidates. Being a field job, it is tiresome and tough for female DCMAs, so drop out ratio of selected candidates is much more among females. Furthermore, getting of any permanent job lures the candidates to quit this job as evident in my case.
As a result, there is shortage of DCMAs and only those candidates are called from waiting list who have undergone the interview process. This time they are intending to maintain waiting list for one year. So all these factors compelling them to call ten candidates per seat.
For male seats, where vacant especially in Abbotabad and other districts, the process is expected to start 15th of May through NTS.
Regards