Does Batch Create Support Adding Existing Users to an Existing Blog

Topic pretty much says it all. I have another plugin that does the same thing (and usually works very well), but it seems to be having some sort of issue and I'm unsure of whether it's a conflict with another plugin or something to do with the recent upgrade to 3.5. Either way, I don't feel like figuring out what is wrong with that plugin if Batch Create can accomplish what I want (i.e., adding about a thousand existing users to an existing blog).