I agree, it's worth checking whether the installer did it correctly.
Note that the procedure said to work for the X850 (which we think is the same for the Z150 and X950) is like the hack for the older 110, 120, and 920 models -- where the secret bypass pin is on the same row as the mute pin.
In the hack for the 130, 930, 140, and 940 models, the bypass pin is on the row above the mute pin. If your installer did your Z150 this way (out of recent habit), it would be wrong.