Given a rank $2r$ matrix $M\in\Bbb Q^{n\times n}$ can we find two matrices $M_+\in\Bbb Q_{\geq0}^{n\times n}$ and $M_-\in\Bbb Q_{\geq0}^{n\times n}$ each of rank $r$ such that $M=M_+-M_-$ holds?

Though $M=AB$ where $A,B'\in\Bbb Q^{n\times r}$ are rank $r$ and we can rewrite this as 
$$M=(A_+B_++A_-B_-)-(A_+B_-+A_-B_+)$$ where $A_+,A_-,B_+,B_-\in\Bbb Q_{\geq0}^{n\times r}$ holds it is unclear $$rank(A_+B_++A_-B_-)=rank(A_+B_-+A_-B_+)=r$$ holds.