^Yea. It's the law actually. These major pharmaceutical companies are not some fly-by-night meth cooks working out of an RV. They're well established and capable of doing things correctly. It would be so totally against their best interests to make Adderall pills that were any weaker than advertised and for what purpose; to save a few pennies at the cost of their reputation?
Their is inevitably gonna be minoscule differences from pill to pill, but the active ingredient is always gonna be the same.