I could not find the relevant answer on above link,anyhow page 193,Book World Constitutions by S.L Kaeley and M Sohail Bhatti Edition 3rd. It goes that sometime the president include the vice presidents in cabinet as matter of courtesy.

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" If you salute your duty,You need not salute anybody,but if you pollute your duty,You have to salute everybody"
(Dr A.Q.Khan)