Well, in that case, I don't agree with you.

The DirecTV dishes differ from C-Band dishes in two important ways:

Both types are based on a parabolic reflector, but the DirecTV dish doesn't cut a circle around the LNB arm but instead shifts the dish cut off of the center so that the arm is not in front of the dish; and

It's not simply a parabola, since it's made to gather enough usable signal from more than one azimuth direction. It's a widened modification of a parabola, extending the aiming abilities laterally along the ecliptic.

Neither of those differences explain why satellites close to one another would be peaked at different elevations. A parallel case for a C-Band antenna would be for you to point a perfectly installed and pointed antenna at the correct azimuth, then find that you have to change the elevation to peak one or more satellites.