=MAX(IF(AND($U11=0,$V11=0),MROUND($S11-$X11,4),IF($X11=0,MROUND($W11-$N11,4),MROUND($W11-$X11,4))))

This formula works. But I am missing something in it. Because when
cell N11 is greater/more than W11. I get the #NUM! error. Otherwise the
calculation is right.

Anyone out there than can help me add the argument that if N11W11 give me
ZERO as will as all the above.

Help! Bonnie