10% of net income does not sound like a good deal at all. 10% of gross revenue for the product would be much better, but still why so little?
It's also 10% of any form, even electronic:
"as a result of our distribution of the book, in any form, printed, electronic, or other, or from the license or sale to third parties of any rights in a derivative work."
Especially since "net income" is basically a made up number. If they buy a new factory to print books out of, they can divide up the cost however they want amongst their authors. Stuff like that. "Net income" is entirely under their control.
It's also 10% of any form, even electronic:
"as a result of our distribution of the book, in any form, printed, electronic, or other, or from the license or sale to third parties of any rights in a derivative work."