Supply chain advisor Stephan de Wit on the planning architecture problem that costs organisations millionswithout showing up on any dashboard.
Most S&OP process failures stem not from poor planning quality, but from a planning architecture that was never designed to work as one integrated system.
When commercial, supply, and financial planning operate independently, organisations end up with multiple versions of the future — and no mechanism to resolve them.
The fix is architectural: a shared planning horizon, early capacity input, and a decision governance layer that turns S&OP from a coordination tool into a true steering mechanism.
When S&OP isn't working, organisations examine forecast accuracy, review tooling, and question process design. Stephan de Wit, supply chain advisor at Quicksilver Consultancy, has sat in those conversations across dozens of organisations and keeps arriving at the same place.
"S&OP assumes that all planning activities work together and are aligned," he says. "In many organisations, a process was never designed to work as one integrated whole. That's where things go fundamentally wrong."
The planners aren't the problem. The architecture is.
Most organisations run plenty of planning activity. Commercial teams map promotions. Demand planners build forecasts. Supply planners calculate inventory positions. Finance produces budgets. Each function does its job.
The problem surfaces when you look at the full picture.
"Every planning process may be optimised with the right people, the right systems, the right data," Stephan says. "But they stand apart from each other. That creates a lot of discussion and very little decision-making."
S&OP gets introduced to bridge the gap. Instead, it absorbs the consequences of it. "Supply reacts to demand planning," Stephan notes, "but not the other way around — even though it arguably should."
The result: S&OP becomes a place to coordinate, not a place to steer.
Stephan points to two organisations where the architecture problem turned operational.
At a large global retail organisation, commercial promotion planning generated demand peaks the warehouse could not absorb. Deliveries ran late, distribution centres overstretched, and external storage became an urgent requirement. The demand had been created without checking whether operations could handle it.
At a second international organisation, multiple plans ran in parallel, independently of each other. "I encounter that in every company," Stephan says. "It comes down to ownership."
Both organisations had planning processes that worked within their own scope. The failure only became visible once someone analysed the architecture end-to-end.
The costs build gradually, through friction that looks manageable until you put it all together.
"S&OP meetings end up explaining differences rather than simulating what the optimal order quantity is, what the optimal inventory level is," Stephan says. "The flow of goods should be optimal. Instead, S&OP becomes alignment."
Each function optimises its own planning process. Commercial focuses on growth. Supply chain focuses on operational reliability. Finance focuses on financial control. No one designs the overall architecture.
S&OP gets added as a meeting structure to compensate. But without structural integration between portfolio planning, demand planning, supply planning, and financial planning, S&OP tries to align plans that were never built to align.
"If you want integrated planning, it has to start at the top," Stephan says. "It's a governance question, a steering question. Not something you can organise at the business unit level. Someone has to feel responsible for it."
The lack of end-to-end ownership is the root cause. And because every team operates well within its own scope, no one experiences the gap directly. It takes an outside perspective to see it.
Organisations that have solved this make one fundamental shift: they stop managing planning as a collection of separate functional processes and start designing it as one integrated business capability.
Stephan recalls a conversation with a leader at one such organisation, asked what made their planning work. The answer: finance had taken ownership as the driving force. Not because planning was a finance problem, but because end-to-end accountability had to sit with someone.
In practice, integrated planning architecture has four defining characteristics:
"Good organisations ensure one integrated process," Stephan says. "End-to-end ownership. Early validation of commercial and supply feasibility. Portfolio governance. Early capacity insight. One shared horizon, one shared process, and clarity on assumptions and goals."
The business case for rebuilding planning architecture isn't only financial. The daily work of planning changes.
"The process becomes simpler," Stephan says. "Faster. Less replanning, fewer versions of the same plan, fewer discussions after the fact. Assumptions from other planners become visible — which makes you far more efficient."
With a shared planning rhythm, planners get time back. Time to run scenarios, model alternatives, and focus on work that actually moves the business. "If you organise things well upfront," Stephan says, "you create time. Time to simulate. Time to make planning stable and reliable."
Stephan closed the webinar with three questions for any planning team ready to look honestly at its architecture:
"If these questions create debate in your team," Stephan says, "that's usually where the real opportunity is."
Improving S&OP rarely starts with the meeting itself. It starts with what sits around it.
When commercial, supply, and financial planning share a horizon, share assumptions, and feed into a clear decision governance layer, S&OP becomes what it was always meant to be: a place where cross-functional trade-offs get resolved and the business gets steered forward.
"S&OP should be steering," Stephan says. "Not alignment. That's the essence of the problem."
The planning processes feeding into it were never designed as one system. When commercial, supply, and financial planning run on separate timelines with different assumptions, S&OP absorbs the gaps. It explains differences rather than resolving them.
Five issues appear consistently: commercial planning disconnected from supply; portfolio decisions made outside the planning cycle; capacity planning introduced after commitments are already made; parallel planning processes running on separate assumptions; and no governance layer for cross-functional decisions.
A shared tactical horizon of 6 to 18 months across commercial, operational, and financial planning. Commercial and portfolio input validated against supply feasibility early in the cycle. Capacity constraints incorporated while plans are still adjustable. S&OP functioning as a decision moment rather than a reporting session.
The accountable function varies by organisation. The principle doesn't: end-to-end ownership must sit with one function or role that has cross-functional authority. Distributing that responsibility across departments is how the governance gap opens.
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