Mine is on my 2nd story and my house sits above the street, so it is probably more like 3rd story height difference from cam to street. I have a worse angle than yours and going out 165 feet and still get plates.
We have all adjusted ours after initial set-up as we realize we miss something. I had mine on the first floor about 10 feet up for a year and decided to move it to 2nd floor so it wasn't as obvious and no change in quality. Actually I could even go out a little more in distance now as a mailbox was in the way at the 1st floor level and now I can catch vehicles from a dead-end street too.
Like I mentioned earlier, I decided to zoom in even tighter to improve the percentage being viewable. That is even more important if you ever decide to "automate" the reading with Plate Recognizer or OpenALPR, your FOV will send so many photos not of vehicles. Being in a cul-de-sac, you could probably get by with the free version of Plate Recognizer, but that would be dependent on not sending lots of non-vehicle pictures.