Hasan Kawun Kakar, Government and Society in Afghanistan: The Reign of Amir ʿAbd al-Rahman Khan, Austin, Texas, 1979. This author has done the most work to date on Afghan administration between 1880-1900. He seems to treat the two terms as generic rather than specific ones, although that may be a misinterpretation on my part. See his glossary for both terms and the slightly different way he treats ʿāmel and zābet in the text, pp. 57, 77f, 80, 85.