Dual z motor leveling

So Is there a way to invert the Z adjustment? when i run 2 motor z leveling the leadscrews turn in the oppsite direction. is there a way to invert it ? here is my current set up
i have drivers 2 and 4 driving my z motors.
M671 X20:400 Y200:200 S10 ; leadscrews at left and right of X axis
M558 P8 H7 F200 T10000 I1 A10 S.005
G30 P0 X20 Y200 Z99999 ; probe near a leadscrew, half way along Y axisG30 P1 X400 Y200 Z99999 S2 ; probe near a leadscrew and calibrate 2 mot
M558 P8 H7 F1000 T60000 I1 A10
thanks!! 
try swapping the x coordinates
M671 X400:20 Y200:200 S10 ; leadscrews at left and right of X axis

or swap the connectors of the 2 z motors

As @Veti says. You must declare the coordinates of the motors in the same order in M671 as you declare the associated driver numbers in the Z parameter of M584.