Recently had 2 x front tyres fitted. One in July and one 2 x weeks ago. However, 3 x tyres are at 30 psi and one at 33psi (newest one). I deflated this (as I have a gauge) to the same but no alarm triggered. I have a feeling that the person that changed the tyre has not swapped over the sensor. Who is responsible for that ? The guy fitting the tyre or does it lie with me to inform him?. I just assumed that they would have noticed this