Difference in Ast required in staad result and RCDC Result in Column Design


I am analyzing one building model in STAAD and RCDC and I am getting difference in the Ast (required) in STAAD and RCDC Result. Please help me to know the reason behind it ?

Column no 64 in STAAD corresponds to Column No C21 in RCDC -

Ast requried in STAAD - 1158 sq.mm

Ast (provided) in RCDC -  803.84 sq.mm