For the purpose of determining eligibility for a SPA, the Applicant performed higher level functions from the date of the issuance of a vacancy announcement for the higher-level post until the selected candidate assumed the higher-level post. As he performed the higher-level functions for less than four months, the Applicant failed to meet the eligibility criteria under ST/AI/2003/3. The Applicant did not satisfy the criteria for SPA and that the Administration’s decision not to pay it was lawful.