"The Woman in Me" has reportedly sold 400,000 copies thus far, Britney gets 25% of net profits

I know TMZ is trash, and they make a habit of undermining & attacking Our Queen. Britney is pulling in 25% of the net profits from the book. Sources with direct knowledge tell TMZ, the 25% Britney is getting should cover the advance she got -- $12.5 million. There have been reports she received a $15 million advance, but we know it's $12.5 mil. More than 400,000 copies have been sold, and the trajectory could take the book north of a million. But really? Only 400,000? Even though there was a 9,000,000 rumor, a 15,000,000 rumor, and Britney saying herself that it was the highest selling celebrity memoir in history? I want official reports from the publishers!