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Per Series, Per Profit: the tiny checkbox that changes your margins in D365

  • Beau Schwieso
  • Aug 25
  • 4 min read

If your BOM eats an extra handful of parts every run, it is not hungry. It is misconfigured.


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Why “Per series” exists

Not every component scales 1:1 with output. Some costs are fixed per run. Think setup kits, lubrication packs, catalyst charges, QC swabs, or that one box of screws you open once per build. In D365, those belong to constant consumption and the Per series field controls how often that constant applies across the order size. Use variable when usage grows with quantity. Use step consumption when usage jumps at thresholds.


Translation: Per series is your “apply this fixed amount every N finished goods” knob. If N is 1, it applies once per order. If N is 100, it applies once for each 100 produced. The field lives on BOM and formula lines.


The mental model: Constant vs Variable vs Step

  • Variable: usage scales with quantity. Great for raw fabric, resin by weight, fasteners by each.

  • Constant: a fixed quantity per order or series. Pair it with Per series to define the series size.

  • Step consumption: fixed amounts that change at quantity thresholds using From series rows. Perfect for line setup kits that get added again at 100, 200, 500 units.


Where to click

BOM line or Formula line → Line details → Setup tab

  • Consumption is: Constant or Variable

  • Per series: enter series size for constant usage

  • Step consumption tab: add From series and Quantity rows when using Step consumption


Three industry patterns with numbers

Discrete manufacturing: fasteners by pack, not by piece

  • You include a setup screw kit of 1 pack every Per series = 50 finished units.

  • BOM line: Consumption = Constant, Quantity = 1 pack, Per series = 50.

  • If you produce 240 units, the kit applies 5 times. That is predictable, auditable, and cost rolls up correctly.


Process manufacturing: catalyst per batch

  • Your reactor requires 0.5 kg of catalyst for each standard batch of 1,000 liters.

  • Formula line: Consumption = Constant, Quantity = 0.5 kg, Per series = 1,000 L.

  • If the batch order is 2,400 L, the catalyst applies 3 times. If usage jumps at larger sizes, switch to Step consumption with From series thresholds.


Food and beverage: spice blend per cook

  • Each cook adds 1 blend pouch regardless of 80 vs 95 trays, but at 120 trays you open a second pouch.

  • Formula line: set Step consumption with rows

    • From series 0 → Qty 1 pouch

    • From series 120 → Qty 2 pouches

  • The system selects the correct row based on order size.


The four mistakes that wreck margins

  1. Leaving constant items as variable

    1. You silently over-consume on small orders and under-apply on large ones. Fix the line to Constant and define Per series.

  2. Using Constant without Per series

    1. You meant “every 100,” but configured “once per order.” Costs drift as orders scale. Use a meaningful series size. Field is on the line details.

  3. Faking thresholds with spreadsheets

    1. Use Step consumption. Create clean From series breaks. Stop asking planners to remember tribal math.

  4. Forgetting cost roll-up reality

    1. If you do not model fixed and step usage, your BOM calculation lies to you. Roll-ups respect these settings.


Test it like a pro in USMF

  1. Create or pick a finished good.

  2. Add a BOM or Formula line. Set Consumption = Constant, Quantity = 1, Per series = 100.

  3. Estimate three orders: 80, 100, 220.

  4. Verify consumption fires 0, 1, 3 times.

  5. Flip to Step consumption with rows 0→1, 200→3. Re-estimate and confirm it selects the correct From series row.


Costing and planning notes

  • Cost roll-up: Constant and Step usage roll into standard and planned costs, so your item cost reflects reality.

  • MRP impact: Master planning will plan fixed components based on these rules. If Constant or Step is wrong, planned purchase quantities will be wrong too.

  • By-product costing tip: Elsewhere in D365, “Per series” can mean cost per standard batch size that is independent of reported quantity. The idea is consistent. Know which flavor you are using.



Guardrails and gotchas

  • Rounding and multiples: If your fixed item is picked in full cartons or odd lengths, combine Constant or Step with Rounding up and Multiples so consumption reflects handling units.

  • Scrap location: Constant scrap is not the same as constant consumption. Model the real driver, then apply scrap where it belongs.

  • Documentation: Add a line-level comment that explains why the item is Constant and the choice of Per series. The next engineer will thank you.



Copy-paste checklist for your next BOM or Formula review

  • For each line, answer: Does usage scale with quantity

    • Yes → Variable

    • No → Constant with a meaningful Per series

    • Jumps at thresholds → Step consumption with From series rows

  • Validate cost roll-up after changes

  • Run a small, a standard, and a large order as regression tests

  • Capture screenshots and the estimation report for Audit





Right qty, right cost, right now.

DynamicsDad

 
 
 

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