Quantity drop down have problem

i want quantity step as drop down box

in stock : 9999

quantity step : 1

list quantity step : 10

and success , i have quantity box with drop down list from 1 - 10

but i have problem.

when add to chart

i have 2 notice

The quantity of the product Organic Arborio Rice in your cart has been changed to allowable.

The product(s) have been added to the cart

, no product add to cart. please help us to fix it.

cs cart version : 2.0.6