As far as I can tell nothing has changed with Ancestry's end. What you are describing has to do with the census records themselves. If memory serves me right, it was the 1880 census that began to list the relationships of people in the household. Previous census records did not have the info available to differentiate between relationships of people listed. So, if you add a census from 1880 - 1940 you will get the ability to add family members at the same time. Previous census records will require you to figure out who is who and add the record to each member of the household individually.