I tried using TST tire pressure sensors on the braided stainless steel extensions provided by PC without any success. For some reason the valves in the braided extensions were not compatible with the sensors. I even had difficulty using hand held gauges and putting air in the tires.
I did away with the rear wheel valve extensions by having one piece Borg brand valves installed on all rear tires. After this valve replacement all previous problems with checking, airing up, and using the remote sensors went away. The sensors provide a higher level of confidence by knowing the tire pressure is within an acceptable range and if some issues are developing that causes an increase in tire temperature. While this pressure system probably has little benefit in preventing near instantaneous blowouts caused by road debris it can give one early warning if the pressure starts to decrease or temperature unexplainably starts to increase.
Perhaps the new Phoenix models don't have the same valves and extensions as my unit but if so and you encounter the same problems as I did there is a relatively simple though not inexpensive fix.