Unfortunately. This plugin doesn't really seem to work on large networks of about 1500 users. If I use the add from network feature, there are too many users in the form, and the POST data is getting cutoff around 1000, and post processing breaks because the submit button isn't included and that is needed for it to process. So you get this: "Unknown request. Please select the Add from Network option to try again."
When I use the add multiple entries feature, it only adds the first entry. Not sure why that happens.
Nice plugin on small sites though. Very handy.