The phrase "additional millions" means a large number of extra millions, indicating a significant amount or quantity added to an existing figure. Full definition
Traditional publishers noticed her success, and she has gone on to earn additional millions as a bestselling author. (blog.infinitypublishing.com)
In addition, many charters are subsidized by additional millions of dollars in private donations, which enables them to market their wares and provide services that regular public schools can not afford such as tutoring and mandatory summer school. (saturdayeveningpost.com)
Considering Macmillan estimates that more than 2 million copies have already been sold across all formats, Comey could be looking at additional millions in the coming months if sales continue at such a high pace. (gobankingrates.com)