Planning worksheet/ planning parameters

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Posted on by Max Barker

Hi all,

We're trying to improve our purchasing method (started with a lot of custom fields, wanna go more standard). We feel like using the Planning Worksheet is the right way to go, but we're still facing some hick-ups on our side.

Quick intro, we've got stock and non-stock items. For both types of items we think using Lot-for-Lot is the way to go and we use Safety Stock as re-order point actually for the stock items. This also is the first question, is Lot-for-Lot the best way of planning Stock items?

For now we used Lot-for-Lot in this case.

Stock = 5

Qty in Purchase order = 5

Qty in Sales order = 0

Lot accumulation = 14D

When we run the Planning worksheet it gives us a quantity of 5 to order, but we've got already 5 in another Purchase order which will has a date of 01-10-2025.

Why does the Planning worksheet gives us 5 to order?

Hope anyone can help us further.

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Dynamics 365 Business Central

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André Arnaud de Cal... 305,354 Super User 2026 Season 1 on at

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As the screenshot indicated, this is Business Central, I moved the question from the Dynamics 365 SCM to the Dynamics 365 Business Central forum.

1 people found this reply helpful.

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Ben Baxter 7,099 Super User 2026 Season 1 on at

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You're heading down the right track.

Should you be using the Planning Worksheet? 100% Yes, everyone should!

Can Lot-for-Lot be used as a Stock policy? Absolutely!

Is Lot-for-Lot the best Stock policy? No, Fixed or Max is the best true stock policy. But neither policy accounts for variable demand as well as Lot-for-Lot does.

The big question, why is it suggesting you order more when you already have 5 on order?

Because you're out of (safety) stock. Sidenote, I'm assuming "Stock = 5" means Safety Stock of 5 and Quantity on Hand of 0.

What the system is probably doing is suggesting you cancel your existing PO and create a new PO in the past (which isn't a real possibility). To combat this, you can adjust your Start Date in the Calculate Plan process to when you can realistically get product in, at which point the PO will have landed and counts as Stock. Another option is to try switching the "Planning Flexibility" on the PO line to "None", which means the planning can't offer the cancel suggestion.

Hopefully one of these suggestions will help quiet down the noise for now. Remember Lot-for-Lot is reliant on running the plan with a forward look capable of keeping your stock levels up.

Since you are using Lot-for-Lot, be sure the "Respect Planning Parameters" toggle is turned on during the Calc. Regen. Plan in the Planning Worksheet.

P.S. This answer did NOT use any AI assistance.

Best Regards,

Ben Baxter

Accent Software Inc

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Valentin Castravet 32,748 Super User 2026 Season 1 on at

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Hope this helps as well, this is the best guide I've seen on setting up MRP - Guide to Successful MRP in Micrsosoft Dynamics NAV | Olof Simren - Microsoft Dynamics NAV & 365 Business Central Blog

Valentin Castravet
Work: Zander ERP Services
Blog: Dynamics 365 Business Central Insights
LinkedIn: www.linkedin.com/in/valentin-c-0500a247/

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YUN ZHU 101,723 Super User 2026 Season 1 on at

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Hi, hope the following can give you some hints as well.

https://learn.microsoft.com/en-us/dynamics365/business-central/design-details-planning-parameters#optimize-when-and-how-much-to-reorder

Thanks.

ZHU

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Rishabh Kanaskar 6,229 Super User 2026 Season 1 on at

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Hi,

The Planning Worksheet in Business Central ignores future supply dates outside the net requirements calculation window if the order date doesn’t fall within the planning horizon or if the system isn’t set to consider planned receipts properly.

1. In your example:
> You have 5 in stock and 5 on a purchase order with a delivery date of 01‑10‑2025.
> The Planning Worksheet sees that you currently need 5 units today (or based on your planning date) and the existing PO arrives after the requirement date.
> Since Lot-for-Lot calculates orders to exactly cover net requirements at the time of planning, it generates a new order for 5 units.

2. To prevent this:
> Make sure the Planning Horizon and Reorder Policies account for future receipts.
> Verify “Include Planned Receipts” is enabled in the Planning Worksheet.
> Ensure the Order Date on existing POs is within the Required Delivery Date range.

Lot-for-Lot is fine for stock items if you want exact quantities to cover immediate needs, but if you want to consider future receipts automatically, you may need to combine it with Safety Stock and proper planning dates.

Thanks

Rishabh

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Sumit Singh 11,797 Super User 2026 Season 1 on at

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Hi Max,

This happens because of Safety Stock and Lot-for-Lot behavior in Business Central:

Lot-for-Lot: This policy plans to cover net requirements within the lot accumulation period. It does not consider reorder points like Fixed Reorder Qty. Instead, it looks at projected inventory versus demand and safety stock.

Safety Stock: If you use Safety Stock as a reorder point, the system ensures that projected available inventory never drops below Safety Stock.

In your case:

Current stock = 5

Purchase order = 5 (due on 01-10-2025)

Safety Stock = (assumed > 0)

If the planning start date and lot accumulation period include a time where projected inventory falls below Safety Stock before the PO arrives, the system suggests an additional order to maintain the safety level.

This is expected behavior because the planning engine uses projected available inventory (not just on-hand + future supply) to decide when to replenish. If the PO due date is later than the point where safety stock would be breached, it triggers a new suggestion.[1][2][3]
Is Lot-for-Lot the best for stock items?

Lot-for-Lot is ideal for demand-driven replenishment (e.g., make-to-order or variable demand) because it plans exact quantities per period.

For stock items with stable demand, Fixed Reorder Qty. or Maximum Qty. is often better because they work with reorder points and avoid frequent small orders.

Best practice:

Use Lot-for-Lot for non-stock or project-based items.

Use Fixed Reorder Qty. for stocked items with predictable demand.[1][3]

Official Docs:

Design Details: Handling Reordering Policies

Design Details: Planning Parameters

Setup Best Practices: Planning Parameters

References
[1] Design details - Handling reordering policies - Business Central
[2] Design details - planning parameters - Business Central
[3] Setup best practices - planning parameters - Business Central

Please mark “Verified” if it helps.

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Jeffrey Bulanadi 9,123 Super User 2026 Season 1 on at

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Hi Max,

Lot-for-Lot with Safety Stock can look clean on paper, but the Planning Worksheet doesn’t always behave the way we expect, especially when future-dated supply is involved. I totally get why this feels off, especially when you're trying to move away from custom fields and lean into standard behavior.

The issue here is timing and how BC interprets availability. Even though you’ve got 5 units on a purchase order, if that PO’s expected receipt date falls outside the Lot Accumulation Period (14D in your case), the system won’t count it as available supply. It’s not ignoring your PO, it’s just not recognizing it within the planning horizon.

Here’s what I’d recommend checking:

Confirm the PO’s promised receipt date is within the Lot Accumulation Period. If it’s outside that window, the system will still propose replenishment, even if the PO technically covers the need.

Review the Planning Flexibility setting on the PO line. If it’s set to “None,” the system won’t reschedule or cancel it, even if it’s redundant.

Safety Stock acts as a floor, not a buffer. So if your projected inventory dips below that threshold, even temporarily, the worksheet will propose replenishment to restore it.

Consider adjusting the Rescheduling Period or Dampener Period to give the system more leeway in recognizing near-future supply.

If you’re using SKUs, make sure the planning parameters are consistent across locations. Mismatches there can cause unexpected suggestions.

Helpful Reference
Planning Parameters in BC - Mad About BC
Navigating the Requisition Worksheet with Lot-for-Lot and Safety Stock in BC
Design details - planning parameters - BC | Microsoft Learn
Design Details - Supply Planning - BC | Microsoft Learn

If you find this helpful, feel free to mark this as the suggested or verified answer.

Cheers
Jeffrey

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Nimsara Jayathilaka. 5,128 Super User 2026 Season 1 on at

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Hi

The Planning Worksheet suggests ordering 5 units because the existing PO arrives after the requirement date, so BC sees a net shortage on the day the demand is calculated. Adjust lead times, accumulation period, or check requirement dates to fix this.

Thanks

Nimsara

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