(1) Under regulations prescribed by the Secretary concerned and to the extent provided for by appropriations, when a member of the National Guard or a reserve component of a uniformed service who is entitled to compensation under section
206 of this title performs diving duty, pursuant to orders, such member is entitled to an increase in compensation equal to 1/30 of the monthly special pay prescribed by the Secretary concerned for the performance of diving duty by a member of comparable diving classification who is entitled to basic pay under section
204 of this title. Such member is entitled to the increase
(A) for each regular period of instruction, or period of appropriate duty, at which the member is engaged for at least two hours, including that performed on a Sunday or holiday; or
(B) for the performance of such other equivalent training, instruction, duty, or appropriate duties, as the Secretary may prescribe under section
206 (a) of this title.