Any commission issuing under the provisions of this subtitle shall, where the rank remains unchanged, bear the date of the commission held on Feb. 18, 1909; and any officer who has served continuously in the same grade may be recommissioned with rank from date of his original commission to that grade.
D.C. Code § 49-802
The reference to "this subtitle" in this section includes all sections of Subtitle I of Title 49 except §§ ,49-217, 49-303, and 49-906.