why the frequency response of AC sweep of Plecs and Linear Analysis tools of simulink are not the same?

Hello,

I am getting different cutoff frequency from AC sweep and linear analysis tools of Simulink as You can see in teh attached files. I have used the demos of plecs:Open-loop transfer functions of a buck converter using AC Sweep Analysis to implement the 02 methods and I getting different cutoff frequency from the same circuit. I am using this to check whether I will use it later on my own circuit (boost dcdc converter). so please let me know why there is such difference in bode plot