Clear Title through Registered Will ?

My mother made her Registered Will in 1995 and made me the Sole Executer and Sole beneficiary of all her movable & immovable properties which were all her Self acquired properties. She died in Feb 2003. She is survived by besides me, my father & my married sister. My father is staying with me ever since the death of my mother and I’m in continuous possession of all immovable properties. On the basis of her will the immovable properties were mutated in my name in the records of MCD in 2004. In year 2011 I reconstructed our residence (bequeathed to me through will) and before starting its construction, I applied for various related permission from various government departments and after perusal of the documents / will, I was given the necessary permission, as the owner of this property, to construct the new Floors. Now I want to dispose ONE of the floors. Many property dealers are giving opinion that I should have PROBATE the Will or in the alternative to get RD from other survivors. My view is that we are residents of Delhi and the properties are also are in Delhi where the PROBATE is not essential. Further, the concept of RD is altogether a different ball game. Getting RD from other survivors essentially means ADMITTING that they had the rights over the properties during all these years which they are relinquishing and which I believe is incorrect, in view of the Registered Will. What is your opinion?