Right now the sort by "modified" date only refers to the very top level of the Drive. But If I'm adding files and folders to a top level folder that I created 3 years ago, that top level folder is still way far down on the sort list. If I'm doing a lot of work in one directory and frequently modifying the contents and/or subdirectories, I would expect that to be reflected in the top level, but as it is I have to do a lot of scrolling and manual scanning on each layer to get to the same folder over and over.