I don't understand the fender thing. The bumper and fender are two separate parts. One doesn't have to be replaced because the other is damaged.

Painting the hood is a blend so the paint matches. However, if a fender is replaced, it is the adjacent door that would get the blend. The hood, because it is on a different plane and curve, probably wouldn't require a blend.

However, if the bumper is replaced, the right fender might have to be blended as well.

This is how the work is done so that it is like new and most good shops will do it that way because customers like the results and they don't get into arguments about color matches and such.

Gets expensive, but there is no alternative other than to accept lesser results. Vehicles are not made to be repaired and the parts are obviously too expensive.