Minimum lot charges
Interpreting supplier minimum charges by lot, process, line, and invoice, with reconciled examples that distinguish billing from internal unit-cost allocation.
Tags: costing, supplier-pricing, lot-costs, allocation
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Meaning and scope
A replacement floor bills the greater of the stated minimum and extended processing value. Marsh Plating applies its minimum when the per-pound or per-piece finishing value is lower. Marsh Plating terms
In the worked example, 10 pieces at $4 extend to $40. A $180 replacement floor plus a separately quoted $25 certificate gives $205. If $180 were an additive setup fee instead, the same figures would total $245. Confirm the quote’s process, lot or invoice boundary before applying either model.
A billing minimum sets the charge. A minimum order quantity sets how many parts the supplier will accept. A quote can contain both a floor and additional charges.
Identify the charging boundary
Published examples demonstrate why purchase-order count alone is insufficient:
| Boundary | Published example | Estimating implication |
|---|---|---|
| Process | Gleco says each offered process has a minimum lot charge. | Multiple processes can create separate floors. |
| Line item | Gleco also defines a minimum line-item rule. | Combining lines on one PO does not necessarily eliminate minimums. |
| Processing line/setup | Technical Plating says an order using multiple lines has a setup charge by line. | Confirm which routes or lines the work requires. |
| Invoice | Metal Finishing Company lists a minimum charge per invoice. | A process minimum and an invoice minimum are different levels. |
These are supplier-specific policies, not interchangeable definitions of “lot.” Gleco terms, section 3, Technical Plating policies, Metal Finishing Company minimums
Gleco's Rev A, effective July 25, 2026, specifies that each line is charged at the greatest of its extended value, its applicable line minimum, or the process minimum divided by the number of PO line items. It states a $20 line minimum unless the quotation specifies a higher one, and says process minimums are available on the quotation. Apply this detailed rule only where those terms govern; do not simplify it into a generic “one minimum per PO.” Gleco pricing terms
Metal Finishing Company's page identifies January 1, 2026 implementation, lists process-specific amounts, and separately states a $150 invoice minimum and a 2% minimum energy/environmental surcharge. It also says prices and lead times may change. These published figures illustrate stacked charging boundaries; obtain the actual quote and confirm the surcharge calculation rather than treating the page as a guaranteed total. MFCO minimum charge schedule and notes
A simple floor model
Where the quotation expressly defines a replacement floor, use:
Base processing charge = max(minimum lot charge M, quantity q × unit price p)
Effective processing charge per part = base processing charge / q
For weight- or area-based quotations, replace quantity with the stated billable measure and preserve its units. This model describes the replacement-floor behavior published by Marsh; it does not include taxes, freight, testing, or other items unless the quote says so. An additive setup model would instead be setup fee + q × p, and produces a different result. Marsh minimum-charge policy
Original illustrative example, not supplier prices: assume a $180 replacement minimum, $4/part processing rate, and a separately additive $25 certification charge. No taxes, freight, scrap, or other fees are included.
| Quantity | Extended processing value | Billed processing | Certification | Total | Total/part |
|---|---|---|---|---|---|
| 10 | $40 | $180 | $25 | $205 | $20.50 |
| 45 | $180 | $180 | $25 | $205 | $4.555… |
| 46 | $184 | $184 | $25 | $209 | $4.543… |
The threshold is M/p = 45 parts: above it, processing follows the unit rate. It is not a profit break-even point. At 10 parts, mistakenly adding the minimum to the extended value would produce $180 + $40 + $25 = $245, overstating this defined quote by $40. If the supplier instead quoted an additive setup fee, that addition could be correct; the wording decides.
Splitting, combining, and technical compatibility
Separate original example: twenty parts at the same $4 rate and $180 minimum cost $180 as one eligible lot, excluding all extras. Two independently chargeable lots of ten cost $180 + $180 = $360. The arithmetic establishes a possible saving only if the supplier accepts one lot under the same price and processing requirements. It does not authorize mixing materials, specifications, colors, or traceability groups.
Technical Plating's policies describe minimum setup charges by line and separately identify possible fixture, cleanup, masking, baking, certification, delivery, and expedite charges. Its quotes are preliminary until the first run. This is a concrete reason to verify both compatibility and inclusions before consolidating orders or assuming a repeat batch has the same total. Technical Plating quote and service policies
Quote interpretation versus cost allocation
The supplier determines the bill under the accepted pricing basis; internal costing determines how the paid amount is assigned to jobs or products. ACCA explains that batch setup costs can be driven by the number of setups and then spread across units in each batch. That accounting allocation does not change a supplier's minimum or establish the supplier's underlying cost or margin. ACCA activity-based costing
Original allocation example: two jobs with 6 and 4 identical parts share an accepted $180 lot charge. A disclosed part-count allocation assigns $180 × 6/10 = $108 and $180 × 4/10 = $72, reconciling to $180. Allocating $180 to each job would double-count the supplier charge. Part count is suitable here only because the example assumes identical processing burden; weight, area, separate masking, or testing could justify a different assignment.
Recalculate the invoice at the new quantity using the lot charge and allocation driver. ACCA batch costing discussion
Information to retain with an estimate
Record quote validity, process and material condition, lot and line definitions, billable units and the order of charges. Resolve mixed-lot eligibility and the basis for each surcharge before quoting a firm total.