Should just 10mg of adderall (dextroamphetamine and racemic amphetamine) xr be really effective?

Possibly: Stimulant doses vary widely. Some respond to small doses; others need larger doses. Usually, inattentive symptoms such as poor focus or high distractability are relatively sensitive to stimulants and may respond to quite low doses, whereas hyperactivity and impulsivity often require higher doses. However, there is enormous individual variability, so each person has to find the dose that works.