Power Class 3 Working Range

Hi,

I am doing some readings on Bluetooth.

There is something that makes me very confused.

In some books and online resources, they say that Bluetooth Power Class
3 devices are operating on a 1mW power and the working range is about 1
meter.

But some other book says the Class 3 device to work on 10m's range.

And also, for a bluetooth chips/module, (let's say it is power class 3)
could we adjust or change its working range? What if I need to specify
a working range, say 2m?

Or is it fixed once after the chip is made?

Thanks

YY