In 10.0.43, a new feature is introduced to 'Keep pegging for approved planned orders'. This feature helps in MTO scenario's. This feature would need to be extended to also 'Keep pegging for firmed orders' because pegging might change after running planning optimization again after firming. Next to that, the parameter should be set on the master plan and/or coverage group and/or Item coverage as the requested behaviour might be different depending on the item coverage group (Similar to the other MTO parameters 'Use latest possible supply')

Following scenario shows why keeping the pegging also for firmed orders can be useful:

1. Create 2 salesorders for the same product, to 'Produce'
2. SO1 with delivery date 13 March, qty of 10
3. SO2 with delivery date 14 March, qty of 2
4. Negative days is set to 2, coverage for the product is 'Requirement'
5. Run Planning optimization, you will get 2 planned production orders, one for each SO
6. That's fine for MTO :-)
7. Firm the planned order associated with SO2, so for a production order of 2 pcs
8. Now run Planning Optimization again, you will get
9. Planned PO for 8 pcs, pegged to SO1
10. Planned PO for 2 pcs, pegged to SO2
11. Set negative days to 0 and set the delivery date of SO1 to the same date as SO2, run planning optimization
12. Planned PO for 8 pcs, pegged to SO1
13. Planned PO for 2 pcs, pegged to SO2

So, even if planning optimization has proposed a dedicated production order for SO2, this is not maintained after firming as then, the firmed production order becomes 'Existing supply' and it becomes pegged to the SO1 instead of 'Keeping it pegged to the SO2' for which it was intended (by the planner). It becomes perhaps even more complex when the production order gets RAF'ed because then we have 'on-hand'. Then the other settings about 'Consume on-hand inventory' and 'Use latest possible supply' come into play as well to influence pegging so the 'Keep pegging for firmed orders' may need to be integrated with those to as an additional option.

'Marking' when firming can solve this but only if there is no 'cut' in the supply chain between the SO and the Production order. Keeping the pegging should be configurable as we understand that it may be conflicting with the 'optimization' of the supply chain. In our situation, there's a transfer order in between (to bring finished goods from production to DC) that we don't firm for operations reasons, so we can't 'mark'.