Washer diameter and thickness do not affect Pullout Strength Results

I am using a hex head anchor in the Profis Anchor software. I included a plate or washer of max thickness (2 in.) and max diameter (6 in.). However, when I change those values, the Pullout Strength remains the same, even though the Concrete Breakout Strength increases or decreases. Why does increasing the washer diameter/thickness not increase the Pullout Strength according to ACI 318-11 Section D.5.3.4?