Castellano® review for Amai Bulk Discount & Sales

Hello, I’m trying to round discounted prices to the nearest full euro, for example 139.90€ with 20% discount should become 112€. I enter EUR 1.00 in the price rounding field, but after saving the rule it automatically changes back to EUR 0.99. Could you please confirm if rounding to .00 is supported, or if this is a bug?