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Summary – Overengineering estimates creates an “invisible tax”: sprawling spreadsheets, endless validation loops and partial integrations that slow decision-making and widen the gap between forecasts and reality. This sterile complexity incurs opportunity costs, lengthens planning cycles and erodes team trust—undermining agility and competitiveness. Solution: connect estimates to core systems (ERP, procurement), automate updates via API and establish governance with an audit trail to restore responsiveness, traceability and reliability.
In many established organizations, the pursuit of a “perfect” estimate has transformed into a cumbersome, complex, and time-consuming process. Spreadsheets amass thousands of rows, committees multiply back-and-forth exchanges, and integration with key systems often remains partial, leaving a false sense of control.
This overengineering of estimates acts like an “invisible tax”: it slows strategic trade-offs, undermines cost transparency, and increases the risk of significant gaps between forecast and operational reality. The goal is not to eliminate detail but to make estimates traceable, integrated, and responsive, turning them into a true performance lever.
The Illusion of Control Through Excessive Detail
Spending hours breaking down every cost item does not guarantee forecast reliability. This quest for granularity increases complexity without strengthening decision-making.
The Obsession with Overgrown Spreadsheets
In many companies, Excel remains the cornerstone of cost estimations. Hundreds of columns are devoted to highly specific items—licenses, daily rates, margins, indirect costs—to the extent that the slightest change requires manually revising nested formulas.
Beyond the risk of human error, this model creates a heavy dependence on a handful of “super users” who master these macros and chained links. The slightest absence or departure of one team member jeopardizes the file’s integrity.
The time spent validating each cell often exceeds the time required to execute a project, generating an invisible opportunity cost that hinders the agility of finance and IT teams.
Endless Review Cycles and Feedback Loops
After each spreadsheet iteration, the document circulates among executives, project managers, and controllers. Each review adds new comments and requests for clarification, extending the validation cycle indefinitely.
Rather than speeding up decision-making, these loops breed frustration and create the illusion that “the more you review, the more you control.” In reality, the data becomes outdated before final approval.
The result is systematic postponement of steering committees, budgets that fail to take effect on time, and delayed key projects, all to the detriment of the responsiveness required in a competitive environment.
Example of Overengineering in a Swiss Context
An industrial company had developed a project estimation spreadsheet with over 500 tabs, each detailing sub-activities and precise hourly rates. With every update to supplier costs, they had to run a VBA script and then manually verify the consistency of the subtotals.
The result: the file became unusable after a few adjustments, requiring over a week of work to rebuild dashboards and recalculate actual margins. This sterile complexity slowed resource allocation and fueled widespread distrust of the planning process.
This case shows that overengineering—under the guise of rigor—can lead to operational distrust, the opposite of the goal of “reliable” estimation. The lesson is to put traceability and integration at the heart of the approach.
The Business Consequences of Overengineering Estimates
Overly detailed estimates turn financial management into an obstacle to action. Decision-making slows down, risks increase, and confidence in forecasts erodes.
Discrepancy Between Forecasts and Operational Realities
When the data used is not linked in real time to core systems—ERP, procurement modules, or project portfolio management—each figure quickly becomes obsolete. Discrepancies of several percent can appear within the first few weeks. A robust ERP implementation links estimation to execution seamlessly.
This gap leads to mid-project budget revisions, requests for additional funding, or complete rework. Teams then become less proactive and more reactive in “crisis management” mode. To centralize these processes, you can rely on a project portfolio management system.
The 2025 CIO report reveals that only 12% of organizations feel “very confident” in their forecasts. This lack of reliability systematizes the creation of safety buffers, artificially inflating estimates and reducing the competitiveness of proposals.
Extended Planning Cycles
Multiple back-and-forth exchanges with the finance department, combined with late-stage committee decisions, can extend planning cycles by several months. A project scheduled for Q1 may not start until Q3, with its window of opportunity sometimes gone.
Lost time is not recovered: in a competitive environment, this can lead to the loss of contracts or strategic partnerships. Internal resources remain tied up in estimation tasks rather than operational execution.
This slowdown also affects CAPEX/OPEX management. Budgets tied up without effective use weigh on cash flow and dilute the expected return on investment.
Example of a Company Facing Delays
A financial services company prepared its annual budget using over 200 interconnected Excel sheets. Committee approvals took three months, causing operational execution to fall out of sync with business priorities.
Result: human and material resources were blocked, the project portfolio was misaligned, and operating costs overran by an estimated 8% of the initial budget. This situation led the IT department and finance team to rethink their estimation framework.
This example demonstrates that planning delays directly impact the ability to allocate resources efficiently and that excessive formality can backfire into a business underperformance.
Edana: strategic digital partner in Switzerland
We support companies and organizations in their digital transformation
Toward Agile and Integrated Estimation
Replacing unmanaged files with auditable systems improves responsiveness and transparency. A few targeted automations are enough to restore trust and accelerate decisions.
Targeted Automations for Rate Updates
Instead of manually reloading each daily rate, you can deploy a script or a custom API connector that pulls current rates from the ERP or procurement module. Updates become immediate and standardized.
These mechanisms ensure that every estimate is based on the latest contractual terms—licensing costs, outsourcing rates, margin adjustments, etc.—eliminating manual tweaks, which are a source of errors.
Automating these flows also records each update in an audit trail, providing full traceability of sources and versions used.
Integration with ERP and Core Systems
Linking estimation data to financial and operational modules avoids duplicated entries and file discrepancies. A workflow can import budget lines directly into the ERP, automatically triggering CAPEX or OPEX commitments.
This bridge between estimation and execution secures budget tracking throughout the project. Leaders gain unified dashboards where forecasts and actuals are compared in real time.
In the long term, you can set up automatic alerts whenever actuals exceed a threshold or if a significant variance occurs, promoting proactive risk management.
Example of a Swiss Group Optimizing Its Workflows
A Swiss institution replaced its Excel sheets with an integrated platform synchronized with its SAP ERP. Each estimate generated a budget entry automatically, and every adjustment was recorded in a versioning module.
The validation phase was reduced from six weeks to two, as data was deemed reliable from the moment of creation. Leaders gained a consolidated view of the project portfolio and CAPEX needs, enabling quick reallocation of resources to higher-impact initiatives.
This case demonstrates that a phased approach focused on integration and targeted automation can unblock strategic bottlenecks without overhauling the entire information system.
Implement Effective Governance and Tools
Coherent estimation relies on clearly defined responsibilities and shared standards. Data governance is the pillar of reliable and repeatable planning.
Define Ownership and Shared Standards
Each estimation item should have an identified “owner”—a financial analyst, IT project manager, or controller. This person is responsible for data quality and applying common definitions.
Documented standards—nomenclatures, cost category definitions, CAPEX/OPEX allocation rules—help homogenize practices across departments and business units.
Establishing monthly review committees for accuracy indicators (actuals vs. estimates) ensures continuous process improvement. Feedback helps refine the models’ reliability.
Establish Audit Trails and Versioning
An audit trail system records every change—who changed what, when, and why. Coupled with versioning, it becomes possible to reproduce an estimate at any given point and understand the history of decisions.
These features are essential for internal audits or board reviews, as they provide full transparency into forecast construction.
In the event of a significant variance, you can trace the source of the discrepancy and quickly adjust assumptions for the next estimation cycle.
Turn Your Estimates into a Strategic Lever
Overengineering estimates creates sterile complexity that hinders resource allocation and increases variance risk. By replacing unmanaged spreadsheets with auditable systems, connecting data to ERP and procurement modules, and establishing clear governance, estimation becomes a performance driver rather than a decision-making bottleneck.
Our experts will support you in defining automated workflows, implementing modular open-source solutions, and establishing a reliable audit trail. Together, we will structure an adaptable, secure framework aligned with your business and financial objectives.
