The Cost You Only Learn About at Month-End
The most common question on a factory floor is simple: "Do we actually make money on this item?" Yet many plants need more than 30 days to answer it. Last month's cost only becomes visible after the monthly close and the accounting settlement are complete — and by then, sales has already booked next month's orders.
The root cause is the gap between standard cost and actual cost. When a standard cost set at the beginning of the year is used for all twelve months, a 15% jump in raw material prices combined with an industrial electricity rate hike can quietly turn a profitable item on the books into a loss-making item in reality. Plants repeatedly discover — three months too late — that a product accounting for 20% of revenue has been eroding operating profit the whole time.
The Data Elements Behind Real-Time Cost
The good news is that most of the raw material for cost calculation is already being collected by MES.
Utilities are usually metered only at the plant level, so allocation is required. A practical approach is to install meters on major equipment and allocate the remainder by rated power consumption × runtime ratio. In practice, metering just 20% of equipment typically explains 70–80% of total power consumption.
Designing the Cost Allocation Model
The core of the model is the hourly burden rate by process.
For example, if a CNC line carries 48 million KRW in monthly overhead against 1,600 baseline machine-hours, the hourly burden rate is 30,000 KRW. Distortion drops sharply when the basis matches the nature of the process — machine-hours for automated lines, man-hours for manual assembly.
Apply activity-based costing (ABC) selectively, only to activities with large per-item variation such as internal logistics, inspection, and die changeover. Once you create more than 30 cost drivers, the maintenance burden outweighs the accuracy gain. Starting with five to eight drivers and expanding only where explanatory power falls short is the safer path.
MES-ERP Integration Architecture
MES manages performance data; ERP manages monetary value. There are three main integration points.
Send performance data via daily batch or event-based API, and until purchase prices are confirmed, apply the most recent receiving price provisionally and adjust the difference at close. With this structure, estimated cost is available on D+1 — pulling the decision point forward by nearly a month.
For dashboards, four views are enough: contribution margin by item, value added per hour by line, profitability ranking by customer, and standard-versus-actual variance (quantity, price, and volume variance).
Rollout Sequence and Validating Results
The biggest payoff appears at the quotation stage. Linking actual cost data to quotes lets you defend a minimum viable price with evidence and screen out loss-making orders before they are accepted. The goal of cost management is not a more precise close — it is a better order decision.
Working with POLYGLOTSOFT
Drawing on our MES implementation and ERP integration experience, POLYGLOTSOFT designs and builds real-time manufacturing cost and profitability management systems. We provide step-by-step support — from assessing the performance data you already collect, to designing the allocation model, implementing profitability dashboards, and connecting the results to your quotation system. If you are considering the shift to a factory where real cost is visible, please feel free to reach out to us.