Found this on supercoder. Says must be given by 8 months in age... Maybe that's why the third one got denied?
For the 3-dose vaccine, the first dose typically is given to the infant at 2 months of age. The second dose is then given at 4 months of age, and the third dose is given at 6 months of age. The first vaccine dose can be given as early as 6 weeks of age or as late as 14 weeks, 6 days of age. Vaccination should not be started for infants once they reach 15 weeks of age. There must be 4 weeks between doses and all doses must be given by 8 months of age.