In the Microsoft Learn area I read about quite powerful logic in Transactions - reduction key
"Transactions – reduction key
Forecast reduction starts with the first (earliest) demand forecast record in the reduction key period. If the quantity of qualified inventory transactions is more than the quantity of demand forecast lines in the same reduction key period, the balance of inventory transactions quantity will be used to reduce the demand forecast quantity in the previous period (if there's unconsumed forecast).
If no unconsumed forecast remains in the previous reduction key period, the balance of inventory transactions quantity will be used to reduce the forecast quantity in the next month (if there's unconsumed forecast)."
https://learn.microsoft.com/en-us/dynamics365/supply-chain/master-planning/planning-optimization/demand-forecast
I have set up Forecast Plan, Master Plan and Coverage Group as documented. But Sales Orders are consuming Forecast only within each period defined via the Reduction Key. i.e. If Sales Orders for March exceeds Forecast for March, I am not seeing consumption of unconsumed Forecast for February.
Further, on searching, I have found no reference to the above functionality other than through the learn.microsoft site. It makes me wonder, is this functionality available - perhaps only from a particular build?