A diabetes management system and method are provided herein that may be used to analyze a patient’s level of control of their diabetes, by looking at the difference between blood glucose measurements taken before and after a meal. The controller improves power converter operating efficiency by regulating an internal power converter operating characteristic depending on a value of a power converter parameter measured after a manufacturing step, or an environmental parameter, preferably employing a table with entries dependent on the parameter value. Packages including a slot or aperture are hung on the upwardly directed retaining tab, and the downwardly directed retain tab is folded over the bottom edge of the aperture, the retaining tabs restrict movement of the package. The inferencing system uses the authentication state to make inferences concerning the problem. In a first time period, based on a first control signal, the energy-storage element and the power-obtaining circuit operate a soft switching so that the energy-storage element is charged to obtain the input line power and generate an energy-storage voltage. When the communications path fails or cannot be established during performance of a downhole operation, a mobile master communication tool that is in communication with the surface system can be deployed within the wireless range of one of the devices to provide an alternative communication path between the surface system and the downhole equipment.