Hi Venkat,
I would like to share a bit on it.
If you are adding a new info object then you have no choice of having your historical data updated in the cube . You may have to reload all the way , by making changes from source.
But on the other hand you want to create a new info object and fill with an attribute of an info object already existing in the cube then , you need not reload for historical data . This is the case when you want to make use of attribute as selection variable for filtering.
Hope it helps.
Thanks & regards,
Sudhir.