In one embodiment, an apparatus and method for implementing intelligent and accurate updates to state-based advanced process control (APC) models are disclosed. In one embodiment, the method comprises receiving at least one of a re-measurement or a data invalidation at a state-based advanced process control (APC) model, referencing a state value table and a state update table to determine the current state of lot measurements in the state-based APC model, updating the state value table and the state update table to reflect the at least one of the re-measurement or the data invalidation, and determining settings to apply to a lot at a process tool based on process variability patterns established by the state-based APC model from the updated values in the state value table and the state update table.