D.C. Mun. Regs. tit. 6-A, § 117
117.1 Captains and Lieutenants may receive pay at their scheduled rate plus a differential of three percent (3%) for regularly scheduled non-overtime work when the majority of their work hours occur between 3 p.m. and midnight; four percent (4%) of their scheduled rate if the majority of their work hours occur between 11 p.m. and 8 a.m.
SOURCE: Final Rulemaking published at 62 DCR 2775 (March 6, 2015).