The time taken by JNTUK to process your OD application solely depends on your luck. My brother had applied at the end of the year around December and did not receive it even after two months while his friend applied for it quite late and received it through post before him. His application status showed pending so he decided to call JNTUK but they refused to help him. He then took his fee receipt and filled out an application at the campus itself and to his relief got the OD within 15 days.
So, try your luck and apply soon as the fees are increased for every convocation.