Some observations of my Oregon Scientific CableFree
I believe the ranges you experience have something to do with the transmitters/sensors.
For example, I had an outdoor temp/humidity sensor that went bad. It would give me 99% humidity. The replacement only gives me 98%.
My wind gauge will give me 2.6 mph minimum.
I guess you get what you pay for.
In my case, my OS is much better than my guess.