Not sure if you are familiar with this. But, I believe it worths covering it …
Have you ever realized NAV Planning goes through different steps or phases of the planning? StartOver, MatchDates, MatchQty, CreateSupply, ReduceSupply, CloseDemand, CloseSupply, CloseLoop. All these steps are being performed on the PlanItem procedure from CU99000854. The way planning goes through each of these steps depends on the reordering policy. But basically:
First state is StartOver which determines if there is any demand to plan for. If so, it try to determines if there is any supply. If this is the case, next state would be MatchDates. If no supply exists, next state would be CreateSupply. If there is no other demand to plan for, next state would be ReduceSupply (if any exists) or CloseLoop (to finalize the loop through all states).
MatchDates state. This is about matching demand and supply dates to make sure that both can be plan together (ie. supply can be used to meet demand). If cannot be met, next state would be CreateSupply (another supply needs to be created). If it can, the existing untracked quantity in the supply needs to be reduced and state would be ReduceSupply.
MatchQty state. If supply quantity is not enough, it needs to be closed (no more available) through CloseSupply state. If this is a supply where quantity can be increased, then CloseDemand state can be next.
CreateSupply state. This is the step where supply will be created depending on the policy.
ReduceSupply state. Here, the untracked (unnecessary) quantity will be reduced from the supply. Next state would be to close the supply.
CloseDemand state. In here, the demand will be closed which means that demand has been planned for. The next thing (state) to do here would be StartOver to start the planning of another demand.
CloseSupply state. This is similar than CloseDemand state but from the supply perspective. If supply has been entirely planned, another supply needs to be considered and StartOver state will be next.
CloseLoop state. This is where planning finalizes. Before doing that, it will determine if ROP has been crossed. If so, it will be planned for again by going through the StartOver state.
Hopefully someone finds the above info useful. Think about a sequence of steps before plan can be considered as finalized. These sequences of steps are being done in the PlanItem procedure through a WHILE loop until plan is done.