Did you read nothing else? That is the best possible case, as measured by someone's particular device under ideal conditions - which simply do not exist for a cell phone or a device in a pocket, backpack, or house.

Civilian grade gps receivers often do not have large antenna, can track only a few active satellites at once (often only processing 3-4 satellites even if they are aware of 20 or more) and only receive a single frequency of signals instead of both available frequencies. You want your device to be thin, right?

All this means your stolen cell phone, in someone's pocket inside of a building is going to have horrible resolution, unless it augments it's position data with other sources such as realtime cell tower triangulation or is in a really dense, previously observed wifi area... which are things not available to these tracker devices.