The phones were tested in an isolated chamber, not connected to any network. It sounds like the test was performed to see how well phones would do given a very ideal and controlled environment so the results are useful as a comparison. Obviously real world results will vary, but this was to see the potential of each device.
"Michael Thelander, Signals Research's founder and CEO, said use of different bands did not cause differences in the devices' performance, given that Band 13 and Band 17 are fairly close together on the spectrum chart. "I'm confident that if we had tested a Moto X phone that supported Band 17 in Band 17 that the results would be largely the same," told FierceWirelessTech"
I'd be inclined to take his word for it considering their expertise in this area. For what it's worth, my Moto X holds a signal incredibly well and in more locations than my old Galaxy Nexus could dream of doing.