Infusion systems, infusion devices, and related operating methods are provided. A method of operating an infusion device involves determining a reference insulin absorption curve for the patient based at least in part on demographic data associated with the patient, determining a contextual adjustment factor based at least in part on a current patient context, calculating an adjusted insulin absorption curve for the patient as a function of the reference insulin absorption curve and the contextual adjustment factor, and determining a bolus dosage of the insulin based at least in part on the adjusted insulin absorption curve.