Your status does inform your values, but we differ in values even if we aggressively correct for social status (as well as upbringing, race, and every other factor). This is a 'nurture vs. nature' issue, where Rawls assumed nature was irrelevant, but was incorrect.

That's not what the veil of ignorance is about. It's not supposed to be a reality, but a thought experiment in order to do the relevant moral choices.