A system for recommending insulin bolus quantities to an insulin user includes a display unit and memory unit coupled to a control circuit with a user blood glucose target stored in the memory unit. The control circuit is programmed to receive the user's current blood glucose value, to determine and display via the display unit a recommended correction insulin bolus quantity if the current blood glucose value exceeds the blood glucose target, to compute a difference value as the current blood glucose value less the blood glucose target, and to produce a modified blood glucose target as a sum of the blood glucose target and the difference value for a lock-out time period if the difference value is positive. Additional correction insulin bolus quantities may be recommended during the lock-out time period if the user's current blood glucose value exceeds the modified blood glucose target.