You're right!! I've just tried that, it fluctuated between 32~38 but never enter the range of 40~50. When it get passed cities where there are lots of buildings, frames rate dropped.
As a conclusion, the most killing factor is the Mirror & Shadow. I turned off Shadow first, that gave me 10+ more frames thus entreing the 40~48 range.
Next I switched off Mirror, wow! It went back to 50~60 and next I changed Horizon Distance to Far instead of Very Far, that gave me at least 18 frames so I ended up in the 70~80 range.
Unlimited is not needed especially for ground objects. I mean how much eye-candy ground objects in TW games give us? They are very primitive houses. Unless you want to check out the screw on the SCUD launcher, you really don't need unlimited ground object details.
Anyway, this D3D9.dll now revives the Series 1 installs, and I'm very happy with it.