Hiuser can provide different concrete grade for column and wall in RCDC in redesign tool. Generally it seems that user maintain same concrete grade at a given particular floor. Thus presently input is as per floor and not as per type of member. i.e. column and wall.we can take this as an enhancement in future.
I think it will be better during design in RCDC,to select the concrete grade of column separately from that of wall.Concrete grade should be divided into two parts one for columns and the other one for walls.