Anyone who can find and provide a solution to this problem will get credit in my next mod. I suggest that you search it with a hex editor.
*Edit- the angle to which the sniper rifle and the rocket launcher can detect light is different.*
*Edit- no, that appears to be a different sensitivity level between the two. I am using a flashlight to light the walls, the rocket launcher has more sensitivity to light (not brightness difference) than the sniper rifle*
To explain what i mean, here are some pictures:
Sniper Rifle

Rocket Launcher

Note that the light is a flashlight and gives off several "rings" of light, each exterior ring dimmer than the previous one. This is why only a semi-circle of light is showing for the sniper rifle. This is some feature that can be adjusted- the sniper rifle has values for this part, but the rocket launcher doesn't.
Of course this is because only the sniper rifle was intended to have night vision. I also noticed a "fog-like" effect that was on the sniper rifle.
So in summary, Phenomena's wphi plugin is incomplete- there are still values left whose locations have not been found. This should be under the "screen effects" section of the wphi, though I am not certain.