Authorize.net is just a terminal. They will never demand any information from you except for the signup, though their legal disclaimer they make you agree to is 10+ pages basically saying they can do whatever they want and you can't hold them responsible. As a terminal, they're a little like just a shopping cart system.
Your merchant account provider probably won't ask for anything more than what they ask at signup like what you sell and where. It's possible some providers could, but I've found they mostly care about chargebacks and that's it. Chargebacks also tend to have the bank sit on them for months before telling the merchants and buyers aren't so quick to file them because they have to do more than clicking a mouse button.
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Merchant request tracking #'s and supplier info? 
