Actual Distance of 2500 sq ft Router

When a router states it has a 2500 sq ft coverage area, what is the actual distance it's suppose to represent?

The radius of a 2500 square foot circle is about 28 feet, so does that mean wifi should reach 28 feet from the router in all directions (including up and down)?

I understand obstructions like walls/floors can change this, but I just wanted to confirm if my basic understanding of this statistic is correct.

Thanks.

My Setup (Cable 1.2Gbps/50Mbps)>CM1150V>X6S>TP-Link TL-SG1024 (24port Gigabit Switch)