A vehicle wheel balancer system having a processing system and a spindle shaft upon which a vehicle wheel assembly is mounted for measurement of imbalance characteristics and forces. The processing system is configured with software instructions to evaluate the remaining imbalance present in a vehicle wheel assembly following the application of imbalance correction weights, and to determine if the remaining imbalance is the result of the vehicle wheel assembly having deviated from an expected rotational position during the time between the measurement of the imbalance and the application of the imbalance correction weights. In the event of such a deviation, the processing system is further configured to provide the operator with a suitable warning to evaluate and correct the mounting of the vehicle wheel assembly before proceeding to rebalance or re-measure the vehicle wheel assembly.