When change rate in invoice , auto discount appeared

hello community .
after changing rate for items in the invoice , a discount was created for that item . that’s cool but what I want is to change the original rate . for example if item A cost 100$ . after changing the rate manually to 80$ . it looks like I made a 20% discount . but no I want to be a 80$ item with 0% discount . is there an option I can set to change this behavior . thank you

If the rate is different than pricelist_rate, it will create a discount or margin based on the difference. You will have to change the pricelist_rate to 80$ instead of rate to avoid this.