Spotlight Cam Advance Motion Detection question

When using the advance settings to control my zone how far away from the camera will it detect motion? The first Ring representative I spoke with when having an issue with the motion alerts advised it would reach all the way to the end of the zone (mine is approx 100 feet) however the next representative advised it's only approximately 20 feet and not the entire zone. Can someone clarify for me please so I know if I need to keep trying to "fix" my camera if it's more than the 20 feet.Thank you