Registration of Family settelment

My grandfather constructed his house in 1940 in Lucknow and left it by will to my father. My father did not make a will before his death. My father had three sons. After fathers death the three children and mother had a amicable discussion and made a Notorised family settlement in which, following division was agreed Son1 1000 sqft (constructed area nil ); Son 2 3200 sft (constructed area1000sft ) ; Son3 3400 sft (constructed area 1000 sft ) Mother agreed not to have any share . The Khasra has been changed to the respective owners in the Municipalty. We understand this agreement should be registered with the sub registrar so that each person can become individual owner of their portion of the property independently, and this is the proper legal procedure. Questions: 1 Is my understanding correct ? Are there any other aspects/issues/problems ? 2 What will the total expenses ( stamp duty, regn fees etc ) for registration of the family settelment ? what is the pro