ERP Replacement of a Legacy In-House System at a B2B Wholesale Distributor — Minus 15% at Go-live, Plus 11–12% After Twelve Months

Challenges

For decades the company had developed its own merchandise-management system — precisely fitted, deeply embedded in the workforce's habits, but without integrated financial accounting, increasingly hard to maintain and dependent on a few key knowledge-holders. For a B2B business with strong logistics across 16 locations this was a growing structural risk: media breaks between merchandise management and finance, manual reconciliation between sites, and no reliable basis for automation. 

Solution

The decision went to a standardised, modern system integrated with financial accounting. Technically the right step — which is exactly why the case is instructive: the right system decision does not protect against the implementation gap, it only moves it to where most projects don't expect it — behind the go-live. What followed was a J-curve: first a measurable drop, then, with targeted countermeasures, a rise above the old level. At go-live, productivity was demonstrably 15% below the legacy system — and the cause was largely organisational, not technical. The heaviest transition load sat with long-tenured, experienced staff: after twenty years in a self-built system, they were part of it, and in the integrated standard system exactly these performers first felt "lost" — familiar shortcuts gone, responsibilities shifted, their implicit knowledge seemingly devalued. Intensifying change management — more on-the-job support, more training, more room for experienced staff to translate their knowledge into the new system — turned the curve. After twelve months, productivity is 11–12% above the legacy system, with a clear path toward the +20% target (not yet reached). 

• A full, honest productivity balance — the dip is shown, not hidden

• Every figure carries its measurement method; measured and target values kept separate

• Plan the change budget proportional to staff tenure, not system complexity

• Price the J-curve into the business case instead of suppressing it

• Experienced staff are the lever, not the obstacle — translating their implicit knowledge is the real value of change management

• The right system decision doesn't close the implementation gap; organisation does