What does a manufacturers recommended distance matter? Wireless clients certainly don't care. They care about signal strength and contention and interference. Yes a manufacturer can say 300' @ -65dbi with clear line of sight. That's best case scenario. Nothing ever works best case scenario.
I work with an Aruba Networks based wireless system of 22 mobility controllers and about 400 AP's. A typical internal antenna AP cost's around $500. Controller's up to $20,000. We have half a million dollars in wireless infrastructure.