Problem in Auto Exposure and HeightFog

Hi, I met a problem when using Exponential Height fog with physical light unit.
here is my test level , I have a directional light with 100000 lux , and a skylight with around 7000cd/m2, the EV value is around 14 .

then I start to add a height fog in the level, I found the fog Inscattering Color is way dark like below.

I try to adjust the height fog Inscattering Color to a very high value around (4000,6000,10000) , every thing start to looks correct.

But when I enter the interior , I met the problem. since the interior has a EV value around 5, if I use the default fog sitting, everything is fine. but if I adjust the fog Inscattering Color to a high value. the interior will be very dark and fog inside will be very dense as well. like the picture shows below.

It seems the height fog insecttering color will not affect by the light , and it also needs be adjust in the area with different EV value.
I remember we adjust the exposure value for the FX in shader using view.PreExposure value.I am wondering if I can do that for the fog as well? or if there is a better way to fix it?
Plz help, Thanks!

Add, I am using the UE 4.22.3 .