Is the order passed by S.P. is legal

Sir, my father was pormoted from the post of sub-inspector of police to inspector of police on 28 feb 2018 the order of pormotion was passed by D.I.G. and on 16 april 2018 he was reverted to the post of sub-inspector of police, the order of revertion was passed by S.P. According to article 311 Extract of Article 311(1) of the Constitution reads as under: “311. Dismissal, removal or reduction in rank of persons employed in civil capacities under the Union or a State.-(1) No person who is a member of a civil service of the Union or an all-India service or a civil service of a State or holds a civil post under the Union or a State shall be dismissed or removed by an authority subordinate to that by which he was appointed.” Sir in my Father's case the appointment authority is D.I.G. does the S.P. has authority to pass the order of revertion having regard to the fact that my father was promoted to the post of Inspector by D.I.G. ?