issue than how accurate the sensor measures pressure. It probably CAN measure (and display) pressure within 0.5 psi. A pressure sensor is not rocket science. But how well a controller (any type of controller) can meet a setpoint depends on a lot of variables. Heck, if you are an incompetent monkey you could easily have an AVC-R set up so wrong that you are overshooting or undershooting by 2 psi.
Z-Jay Vice President - Edmonton Z Car Club 93 300ZX TT - Stage VI