System and methods of controlling diverter placement during stimulation treatments are provided. Data relating to at least one downhole parameter is obtained for a current treatment stage within a subsurface formation. A response of the diverter to be injected during a diversion phase of the current stage on the downhole parameter is estimated, based on the obtained data and a diagnostic data model. Values for diversion control parameters are calculated, based on the estimated response. As the diverter is injected into the formation, an actual response of the diverter is monitored. Upon determining that a difference between the actual and estimated response exceeds an error tolerance threshold, the model is updated. The model is further updated over subsequent iterations of the diversion phase when the actual response is less than the estimated response. Subsequent diversion phases are performed over a remainder of the current stage, based on the updated model.