A great deal of the time you were expected to make them up out of your head. For example, the Ministry of Plenty's forecast had estimated the output of boots for the quarter at 145 million pairs. The actual output was given as sixty-two millions
(George Orwell 1984)
According to this source in this context the word 'million' should be used as singular
Is the plural for the word 'million' wrong in this context?