Updating Work 365 to Allow Discounting in Refund Scenarios

Applies To: Dynamics 365 / Work 365 Billing
Audience: System Administrators, Billing Teams, Customization Engineers

Overview

In Work 365, subscription-level discounts apply uniformly to charges and refunds. When a discounted subscription is refunded, the refund line also carries the discount, which produces a negative discount value on the Invoice Product (Invoice Line).
By default, Dynamics 365 blocks negative values in the Manual Discount (line-level) field, which can cause invoice creation or posting errors.

Goal: Update the Manual Discount field on Invoice Product to permit negative values so discounted refunds post cleanly.

Prerequisites

• Security role: System Administrator or System Customizer

• A non-production environment for first-time validation (recommended)

• Basic familiarity with Solutions and entity field customization in Dynamics 365

Steps to Enable Negative Discounts

1. Open Customizations

   • Go to Settings → Advanced Settings → Customizations → Solutions.

   • Create/open an unmanaged solution (e.g., Work 365 Unmanaged Customizations).

2. Add the Invoice Product entity (fields only)

   • In the solution, select Add Existing → Entity.

   • Choose Invoice Product (Invoice Line).

   • Select Fields only and click Finish.

3. Edit the line-level Manual Discount field

   • Expand Invoice Product → Fields.

   • Open Manual Discount (the line-level money field; schema name typically manualdiscountamount).

   • Set Minimum Value to a sufficiently low negative number, e.g.

     -999,999,999,999.0000
     

   • Save & Close.

4. ✅ This change allows Dynamics 365 to accept negative line-level discounts so Work 365 refund lines that carry discounts won’t fail.

5. Publish

   • Back in the solution, select Invoice Product and click Publish All Customizations.

   • Wait for the publish confirmation.

Validate the Change (Quick Test)

1. Create (or locate) a test Billing Contract + Subscription with a percentage discount (e.g., 10%).

2. Process a refund (e.g., deactivate/apply refund or create a negative NRI that triggers a refund line).

3. Generate the invoice and open an Invoice Line.

4. Confirm:

   • Manual Discount on the line can be negative.

   • Totals (line and invoice) calculate correctly.

Important Considerations

Alternatives (If Your ERP Can’t Accept Negative Discounts)

• Flatten the discount into the line amount: Post the refund line with the final negative amount and set Manual Discount = 0 (requires custom logic/automation).

• Use a credit memo pattern: Some ERPs prefer a separate credit document instead of a negative discount on the line. Align with your finance team’s policy.

Rollback (If Needed)

• Reopen the Manual Discount field and set Minimum Value back to 0.

• Publish All Customizations.

• Re-test invoice creation.

Best Practices

• Document the change in your customization log (solution, date, author, reason, testing notes). Suggested name: Work 365 Refund Discount Customization.

• Add a regression test for discounted refunds to your upgrade checklist.

• Periodically audit refund invoices to confirm negative discounts are posting as intended.

FAQs

Q: Which discount field is this?
A: The line-level Manual Discount on Invoice Product (invoicedetail.manualdiscountamount), not the invoice header discount.

Q: Will this change affect normal (non-refund) invoices?
A: No—those typically carry positive or zero discounts. Allowing negatives only expands what’s permitted; it doesn’t force negative values.

Q: Do I need to change anything in Work 365?
A: No changes in Work 365 are required. This is a Dynamics attribute configuration that enables Work 365’s refund lines with discounts to post without error.