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Question

The Estimated Material Cost in the Shop Order is being reset to zero after backlashing.

  • November 5, 2025
  • 1 reply
  • 62 views
S
Do Gooder (Partner)
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Parent  - MP A (Manufactured), Component - PP A (Purchased)

Both Parts are Lot Tracking

Inventory Valuation Method - Weighted Average

Inventory Part Cost Level - Cost Per Lot Batch

Steps

  1. Create a product structure for MP A with a quantity per assembly (QPA) of 1 pc of PP A.

  2. Receive inventory for PP A into cost bucket 110 at $2 per unit, quantity 10. (After issuing to the Shop Order, on-hand will become zero.)

  3. Create a Shop Order for MP A with a lot size of 10. Disable auto-close for this Shop Order.

  4. Perform Manual Material Issue for PP A to the Shop Order.

  5. Create the Lot/Batch.

  6. Receive the Shop Order and review the Shop Order Cost.

Repeat the Scenario Using Backflush

  1. Recreate the same setup.

  2. Instead of manually issuing materials, enable Backflush for PP A.

  3. Receive the Shop Order and review the Shop Order Cost.

Estimated Accumulated Cost changed to Zero.

Is there a specific reason for this behavior?

1 reply

M
Hero (Employee)
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  • majose
  • Hero (Employee)
  • 307 replies
  • November 7, 2025

Hi Saneeeeeka :-)

Good to here from you again

Couldn’t you ask a less tricky question ? ;-)

I try to answer/comment this, it will be slightly technical and long

How does the system calculates shop order estimate cost for shop order cost components?

I’ll try to describe the priority rules first and then I get back to your bacflush case for a WA cost controlled component, where part cost level is “Batch”.

  1. If the component is WA cost controlled AND has Inventory Transactions before AND has inventory onhand > 0 * then get Inventory Part Unit Cost
  2. Else if part is WA cost controlled or cost per serial get cost and cost source information from Costing (this is typically very hand for project connected shop orders). Here it does not use Lot Batch No or Serial No
  3. Else try to get the cost from Inventory Part Unit Cost (remember we always work on cost bucket level) **  YES this looks a bit strange; we come back here again, but for Cost Source ID functionality and Projected Connected Shop Order we need to do step 2 prior 3. Based on customer experience from the past.
  4. Else get the cost from Part Cost, cost set 1 ***
  5. Else if no “hits” above, get the estimated material Cost from Inventory Part (well configuration id is used when searching)

Okay - digest above for a moment

Before I comment on the “*” above you should now shop order estimate cost is calculated online the first time it is created. Later, for example if you modify component quantities, change work centers, add a new operation, the shop order estimate cost is calculated as a background job. The shop order estimate cost i calculated in background for performance reasons. **** And it is frozen when shop order reach status started.

For shop orders where the manufactured part is WA or Cost Per Serial we re-calculate shop order estimate cost when shop order is not in fully/partially issued state. But here is where “*” and “****” kicks in :-( => The shop order estimate calculation, since it is background, will in your case be calculated after the component is issued. The inventory onhand is 0 and the inventory value is “gone” since you issued the lot.

If you can set an estimated material cost for the component then below steps will mitigate your problem.

** If you calculate cost in costing and copy costs from your working cost set into cost set 1, enabling Capture Cost Source toggle - that will mitigate the problem.

*** If you calculate cost in costing and copy costs from your working cost set into cost set 1 - that will mitigate the problem.

I don’t know if we should go for an online calculation when we face this problem: “But here is where “*” and “****” kicks in :-( => The shop order estimate calculation, since it is background, will in your case be calculated after the component is issued.”

Because we have had oracle locking problems when many transactions at the same time access the shop order estimate calculation.

Wow, this became almost like a novel. I am so sorry for this lengthy answer, but the code and functionality is a bit complex.

Cheers,

Mats


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