Let me clarify the misconceptions about job of Appraising Officer. Govt has taken measures to minimize corruption in FBR and reforms have been made in this regard. In November 2015, the seniorities of Appraising Officers and Valuation Officers were merged to form a combined seniority. Therefore, the fresh intakes would now have a combined seniority and will be called Appraising/Valuation Officers. They will be called Appraising Officers when posted in Appraisement and Valuation Officers when posted in Valuation Collectorate. Moreover, the post of Examiner (BS-16) is declared a dying post and its duties would now be performed by the A/V Officers (view the Job Duties for the post in the FPSC's advertisement). As per my acquaintances in Customs, Valuation Officers as well as Examiners have no powers to exercise and have their palms greased. In addition, Appraisers and even Principal Appraisers are facing dismissals and suspensions over malpractices.
So the gist of the story is that gone are the days when Appraisers were money-making machines. Now, it is only a clerical job. Therefore, do not dream of getting rich overnight( and I hope there aren't any greedy people here). Work hard to boost your country's revenues.