Methods and system for incorporating downhole and surface data with models and adjustment algorithms to back allocate flow rates of commingled zones. The models include fluid flow in the reservoir and wellbore, pressure drop across a choke, and fluid flow in the well completion. The models are coupled with an algorithm for comparing the results from the individual commingled zones to the total cumulative commingled volume and adjusting at least one predicted rate so that they match the measured flow rate over a specified time period. One method utilizes a reassignment factor for the adjustment of the predicted rates. These comparisons and allocation adjustments can be accomplished even when the frequency of the commingled flow rate and cumulative measurements, and the frequency of the predicted rates from the model differ from each other and the specified time period.