For being 18-20” away from the door that isn’t a bad spread. It appears as if the spread at 18” is approx 16”, which is going to equate to an almost ‘square’ spread (width of spread being equal to distance from bulb). That means at 20’ from the bulb the overall width will be approx 26’ across (compensating for overlap in the center of viewing area). Since the vast majority of the standard 2 lane roads are 22’ feet across this is plenty wide enough for what fog lights were designed for; lighting the immediate road for driver to see in low visibility. This also doesn’t compensate for engineered scatter or unintended scatter, both of which widen the light splash.
If you want to widen the light splash; simply angle the floods slightly to the outside. This will decrease the overlap saturation in the center of the road and open the the illuminated area to the outside.
Having driven in the deserts of SoCal and AZ, I can attest that I would prefer to have a good mix of road/center saturation with the overall width. The road saturation being the more important of the 2. Seeing something in time to avoid is better than seeing what the snakes, scorpions and other critters are doing 100’ off the road. Just my $0.02.....