Look on your rim and tire, there should be small painted dots, on my rims (chrome rim) the dot is white and near the vale stem and the tire has a yellow one.
Check the yellow dot on the sidewall of the tire. This dot signifies the light spot on the tire, this dot should be lined up with the valve stem, on most rims (the dot on my chrome rims is the actual "heavy" spot, due to chroming) I have 28g (1oz) on my rims located near the stem.
Where do they have your weights located?
Are the dots (or stem) lined up?