anchor.diff:           END DO
         END DO
   
  -      t = 0.0_ReKi     ! start time at zero
  +      t = 0.0_DbKi     ! start time at zero
   
         ! because TimeStep wants an array...
         call MD_CopyInput( u, uArray(1), MESH_NEWCOPY, ErrStat2, ErrMsg2 )
  
positive.code: 
           ! step 2
     
           CALL MD_Input_ExtrapInterp(u, utimes, u_interp, tDbKi + 0.5_ReKi*dtM, ErrStat, ErrMsg)   ! interpolate input mesh to correct time (t+0.5*dtM)
              
           CALL MD_CalcContStateDeriv( (t + 0.5_ReKi*dtM), u_interp, p, x2, xd, z, other, m, dxdt, ErrStat, ErrMsg )       !called with updated states x2 and time = t + dt/2.0
           DO J = 1, Nx
  
negative.code:    ! Tight coupling routine for computing derivatives of continuous states
     ! this is modelled off what used to be subroutine DoRHSmaster
  
        REAL(DbKi),                         INTENT(IN )    :: t       ! Current simulation time in seconds
        TYPE(MD_InputType),                 INTENT(IN )    :: u       ! Inputs at t
        TYPE(MD_ParameterType),             INTENT(IN )    :: p       ! Parameters
        TYPE(MD_ContinuousStateType),       INTENT(IN )    :: x       ! Continuous states at t
  