I have the same scale (blade scale is what it says on the side and on mine, when i use those little trays to weigh out my bud, it will weigh out differently when i weigh it right on the metal thing, but ive checked my scale and it still says 1.0 when i put a dollar bill on it, id advise you not to use that tray because i think the sides of it get held up by the black plastic part surrounding the metal