Tiered pricing rule applied twice in a sales order with sales agreement

Summary:

Hi folks, I created a tiered pricing rule based on item quantity, then I created a sales agreement with this Tiered pricing adjustment. The thing is: when I create a sales order associated with this sales agreement I get the tiered adjusment from sales agreement and also the adjustment from the price list tiered pricing rule. Which it would be a 10% discount became a 20% discount because it was applied twice. Do you know if is it the expected behaviour, or what am I doing wrong?

Thank you!