Quantity discount question

Hi!! need help urgently please. In the checkout adding products to my cart is getting a discount is like if it is multiplying the price by quantity that it applies discount it just not multiplies the option’s amount with the quantity.

So when i add quantity 1 works perfect, but when i changed it for quantity 2 it makes 50% discount and if I add 3 quantity makes more discount.

Thanks for your help

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