# What is the meaning of this multi commodity formulation VRP in LINGO

Can someone tell me what is the meaning of this multi commodity flow formulation that I got in LINGO ? I have the brief explanation about the model but don't quite understand the logic behind, here is the information and the code:

Decision Variable:
Flo( i, j, c, k) = amount of commodity destined for node c,
carried from node i to node j on vehicle type k;

! Model multi-commodity flow;
! Cannot have flow within a single node;
@FOR( Set( j) :
@SUM( Vehicle( k): @SUM( Set( c): Flo( j, j, c, k))) = 0;
);

! Flow into node j of commodity c = demand for c at j + flow out;
@FOR( Vehicle( k):
@FOR( Set( j) | j #NE# Depot:
@FOR( Set( c) | c #NE# j #AND# c #NE# Depot:
[CFLO]  @SUM( Set( i) | i #NE# j: Flo( i, j, c, k)) =
@SUM( Set( i) | i #NE# j: Flo( j, i, c, k))
);
);
);

@FOR( Set( j) | j #NE# Depot:
! Flow entering j of commodity for j;
[DFLOE]  @SUM( SxSxSxV( i, j, c, k) | i #NE# j #AND# j #EQ# c: Flo( i, j, c, k)) = Demand( j);
! Flow departing j of commodity for j;
[DFLOD]  @SUM( SxSxSxV( j, i, c, k) | i #NE# j #AND# j #EQ# c: Flo( j, i, c, k)) = 0;
);

! Only source of supply is the Depot;
@FOR( Set( c):
@SUM( SxSxSxV( i, j, c, k) | i #EQ# Depot: Flo( i, j, c, k)) = Demand( c)
);

! Any flow on arc i, j of commodity c means arc i, j, k is used;
@FOR( SxSxSxV( i, j, c, k) | j #NE# Depot #AND# c #NE# Depot:
[FORCE]    Flo( i, j, c, k) <= Demand( c) * x( i, j, k)
);


I have tested with small nodes of 3: Here is what I got:

Selected route: 1 - 3 - 2 - 1 (1 is depot)
x(1,3,1) = 1
x(3,2,1) = 1
x(2,1,1) = 1

And the flow variables:

Flo(1,3,2,1) = 9
Flo(1,3,3,1) = 7
Flo(3,2,2,1) = 9


Is the flow not balanced? I mean why is there not have another 7 in there?