Thanks to The_E's new tehcroom stuff I was able to more closely examine the effect of lighting flags on model loook and I've found something potentially concerning.
There's an interesting way that the lighting interacts with PBR and non-PBR assets. PBR assets will have really dark "main" textures which are the only ones ambient light is applied to(well, it also applies to team colours and added decals). This means -ambient_factor does basically **** all for PBR models.
Now, they'll also have bright -reflect textures, like non-PBR models with their -shine textures. This is the only part spec_static actually applies to. Now, static lighting does seem to apply to the "main" texture but it isn't controlled by spec_static.
What this means in practice is that PBR models will mostly be affected by -spec_static while non-PBR ones will mostly be affected by -ambient_factor. -spec static does have an effect but it only makes them shinier when facing light sources. The effect of static lights on their "main" texture can't be controlled via -spec_static.
In my opinion both ambient_factor and spec_static should apply to both the "main" texture and spec. This way modders(and players) would be able to achieve a somewhat similar lighting look for both PBR and non-PBR models which is what a vast majority of mods currently have.
Additionally, for missions where $Ambient light level: is set to 0 or 7895160(120 on all 3 channels, the default setting) or lower any ambient factor below 70.2 will be identical to 0 as it will result in a "final" ambient value below 0.02. This mission ambient setting is used in all MediaVPs missions and a vast number of mod missions as well. Just a note for tweaking defaults.
I've created an imgur album with pictures of what PBR and non PBR ships look like under different lighting settings to demonstrate my point. https://imgur.com/gallery/v8IRA
This might also explain why Spoon saw basically no difference between ambient settings, if WoD is mostly using newer PBR models then you really wouldn't see much of a difference between ambient 0 and 128.