Since there are no "refills" on schedule II medications, each script is viewed as a separate script to be filled on separate days. A doctor can write 3 (or more) separate scripts for the same medication to be filled on 3 separate dates which must include the original date the script was written and the date that the script can be filled (as long as this practice doesn't conflict with state law).

I am assuming that the patient could present all three scripts at the same time to the same pharmacy so that the pharmacist could "hold" them for future need, or the patient could put them up and present them at the time that the script was due. (Kinda like a "post-dated" script)

If I'm wrong, someone can correct me.