Hi Venkata,
When you use Inputable member default format the intersection of input schedule has to be all base members. You can use inputable member default format but it will colour your cell with the colour given in formatting sheet only. It will not change the colour after the input is made in that cell. Lets say You decide to have all inputable member as white in colour and the you want that once the user enters data in any inputable cell it sould change its colour from white to say orange to identify which cells were changed or given input in this case inputable member will be white in colour and changed member will be orange colour in your formatting sheet.
Hope it helps !!
Regards
Nikhil