WEBENCH® Tools: Filtering

Tool/software: WEBENCH® Design Tools

Hi, 

I'm designing a bandpass filter with Quality Factor around 250, the center freq is 40KHz, the bandwidth is around 160Hz.

For WEBENCH filter design, how is MaxQ calculated?

After I inputted my design specs, 0 (Gain), 40000Hz (fo), 200Hz (BW3dB), 0dB (Rp), 400Hz (BWs), -45dB (Asb), the Butterworth filter has MaxQ of 1025, and the Simulation result doesn't make sense to me either. 

Just wondering that with high Q-Factor like 250, is the WEBENCH solution usable? Or am I using this tool incorrectly?

Please advise, thanks!