Validity of a Registered Will in case of Assigned Land in AP and Daughters right in Assigned land

My grand mother (Father's mother) was allotted an assigned land in the year 1990 by Andhra Pradesh Govt., She has one Son (my father) and two married daughters. She had executed a will and registered the will in the year 2004 on my name (Son's son) i.e. bequeathing all the properties on my name . My grand mother was died in the year 2016. Afer her demise I have approached the revenue officer for mutation to transfer the title of land to my name as per the registered will. However the officer is denying the mutation stating that in case of assigned lands Will can not be executed and the same land needs to be allotted to her children. Whether the contention of officer is valid. Further, My father's sisters have submitted an objection letter with the revenue officer stating that they have the right in her mothers property. Whether daughters have right in claiming the assigned land of their mother. when the will is executed and registered by my grand mother, whether her daughters have right in property. Please suggest.