Group delay and phase delay of a filter
When you do a linear sweep, the number of points are spaced out evenly over the entire frequency range. So, in the first example, Point #1 is at 0.001hz, the next point is at 0.001999hz. In the second example, Point #1 is at 0.001hz, the second point is at ~90kHz; you will never see anything useful 10Hz. You want to change to one of the logarithmic sweeps which will perform the number of points / decade (or octave).