I have the Hawkshead system. I liked it because of the replaceable batteries. I bought sensors for all 10 MH wheels and 4 toad wheels. I've had it just over a year now and still can't make it work properly. After I read your post I just went and checked and it reports no sensor on 2 wheels, the left front and right tag. Even without the booster, which I have installed, it should read the sensor 6 feet away. It changes which sensor it won't read, sometimes it even sees all of them. It will often read "high pressure" on the front tires while driving. It says there is 112 psi in them. The unit is set for the tires to read 105 psi and they are actually filled to 100. (by 3 different gauges)
While sitting at a camp site it often gives off its 10 beeps because it suddenly can't find a sensor. The batteries have been changed, the sensors moved to different locations. For whatever reason, I can't make it work reliably and therefore I tend to ignore it. A waste of $500 because I can't believe it.
I would not buy Hawkshead again.
Ken