I'm not quite sure this makes sense? If I get one with a 128GB SSD and what you say is true then roughly 9GB will be in use leaving 119GB free (sounds about right from reports from others). However if I get a 256GB SSD then you're saying Apple will have added an additional 9GB of programs and data to the SSD which isn't present on the 128GB SSD? I don't think that would be the case at all. I would have thought that Apple would have pre-installed the exact same programs and data files regardless of which model I purchase.