I think a correct way to model the charge source would be to use an arbitrary behavioral current source instead, and set the function to the derivative of a voltage source modeling the charge Q(t). The current is obviously the derivative of the charge. The derivative of a function such as: A*sin(2*pi*F*t+phi) is: 2*pi*A*F*cos(2*pi*F*t+phi). You instantly see that it's not going to be just a scaled version of the original, but its amplitude grows as the frequency grows. An AC analysis with a basic current source will thus not give you the same result!

Attached is an LTSpice schematic of what I mean. It looks like it gives a frequency response pretty close to what's in the app note. (With your values: Flow ~ 0.145 Hz, Fhigh ~ 361 Hz.)

Edit: added a picture for quick preview.