Set Max export file size to 50000 NOT batch size


When I go to export a list to CSV I see this note:
The exporter runs in batches of 50000 subscribers per file with a pause of 1 seconds between the batches, therefore the export process might take a while depending on your list size and number of subscribers to export.
I don't know where that batch size is set?
In backend-settings-import/export I set "Maximum number of records in a single export file" at 50000. Does that have anything to do with batch size??? I set the "At Once" setting to 500. It is when I am in the Customer login and try to Export List that I get the Batch Size message. Makes no sense to me.
Thanks Twisted. Didn't think you were online. Another question if you don't mind. When we try to export Campaign Stats and select only 5 campaigns we get a nice CSV file. But we have 24 campaigns in a group and Jyll wants to export all 24. She gets a text file, or something, displaying in the browser with all the data mashed together almost unreadable. I can't remember where the setting might be to fix that.