Dear Shelly,
Your plan is very reasonable. While ADHD tends to be a pretty enduring condition, it's impact can change over the years and children's capacities to manage their symptoms without benefit of medication also change.
A key factor to consider in designing a treatment plan to address ADHD is the degree of impairment the condition prompts. I can see from your description that your son's symptoms, while still observable, do not seem to be impairing his abilities either at school or at home. If he can manage without the medication, it makes sense to proceed without it. If, at any point in the future, the severity of the symptoms and the degree of impairment argue for reinstatement of medication, it's always available.