DFLUX Subroutine - Change direction of my heat source during a specific step

Dear Abaqus Users, 
 

 I'm currently facing a problem with my subroutine program. I modelize the direct metal deposite process by using a goldak flux. My source need to go one way during an amount of step, then stop during one step and go back were it started. I was able to stop my source but the way back seems to don't work.. Can someone tell me how to fix it ? 
 

 This is my code :
 X0a 

 Y0a 
 Z0a 
 welding torch updated position
 X1a = X0a
 Y1a = Y0a
 Z1a = Z0a + V*TIME(2)
 ! node of interest
 Xa = COORDS(1)-X1a
 Ya = COORDS(2)-Y1a
 Za = COORDS(3)-Z1a
 

 initial position where the second path will start
 X0r 
 Y0r
 Z0r 
 ! welding torch updated position (way back)
 X1r = X0r
 Y1r = Y0r
 Z1r = Z0r - V*TIME(2)
 ! node of interest
 Xr = COORDS(1)-X1r
 Yr = COORDS(2)-Y1r
 Zr = COORDS(3)-Z1r
       
      

 

 squareDista = Xa**2 + Ya**2 + Za**2
 squareDistr = Xr**2 + Yr**2 + Zr**2
   
   
   if (KSTEP.LT.5) then 
   if (squareDista.LT.1e-4) then
 Qbool = 1
 if (Za.GE.0.) then
   c = a
   f = 0.6
 else
   c = 4.*a
   f = 1.4
 endif
 Q1 = 6.*SQRT(3.)*Qw*eta*f/(a*b*c*PI*SQRT(PI))
 Q2 = EXP(-(3.*Xa**2/a**2 + 3.*Ya**2/b**2 + 3.*Za**2/c**2))
 Q = Q1*Q2
   endif
   
   FLUX(1) = Q*Qbool
   
    elseif (KSTEP.EQ.5) then 
    
   FLUX(1) = 0
   
    elseif (KSTEP.GT.5) then
   
   if (squareDistr.LT.1.0) then
 Qbool = 1
 if (Zr.GE.0.) then
   c = a
   f = 0.6
 else
   c = 4.*a
   f = 1.4
 endif
 Q1 = 6.*SQRT(3.)*Qw*eta*f/(a*b*c*PI*SQRT(PI))
 Q2 = EXP(-(3.*Xr**2/a**2 + 3.*Yr**2/b**2 + 3.*Zr**2/c**2))
 Q = Q1*Q2
   endif
   
   FLUX(1) = Q*Qbool      
    else 
   FLUX(1)=0
    endif
       
       RETURN
       END