The most important criteria for judging the appropriateness of therapy is its effectiveness at a dose that minimizes side effects. It appears that you and your physician have achieved that goal with the combination of Pulmicort Respules™ (budesonide inhalation suspension) and Xopenex® Inhalation Solution (levalbuterol). One of the most important elements of asthma management is monitoring, with the results of that monitoring used as a guide for the need of more medication or the opportunity to reduce medication, respectively referred to as step-up and step-down therapy.
The measurement of peak flows can be most useful in this regard. But, rather than relying on so-called normal values, for which there is a wide range, it is preferable that you compare your values to your personal best. The personal best being the highest peak flows that you are capable of, at a time when you are symptom free and your lungs are clear. Another way to look at how well your lungs are working is with simple lung function testing, called spirometry, another way of measuring the openness of your airways. With this testing, comparison with 'normal values' has more validity, especially the measurement, FEV1/FVC. You should discuss this with your doctor.
You should stay with your present regimen for 3 to 6 months. If at that time, your asthma is still very well controlled, you and your doctor may decide to cut back on your asthma medicine doses.