on your setup you get 4.75 frames of lag.. that is a fact. on his setup he gets 6.3 frames of lag, that is also a fact. what we need to establish now is... why is your lag lower.. he is using a controller presumably? and you are using a Ps4 controller, maybe the truth lies somewhere in that
also to anyone saying 'you are not estimating the time you press the button' that doesn't actually make sense, you can start counting a frame before he even touches the button and it would still be 5 frames of lag!
I think we need to all agree that he is experiencing lower lag on his setup, and then we need to find out why.. do you have a fightstick you can test also?