Describe the issue
It doesn't make sense that Dampener Period can't be larger than Lot Accumulation Period when planning Lot-for-Lot.
Much more reasonable would be that a minimum of the lot accumulation period is used, and a larger time period can be set by using Dampener Period.
The comment in the code suggests that this was the intended use, and it's a bug that it doesn't work like that. (See CalcDampenerDays() in PlanningGetParameters.Codeunit.al)

Expected behavior
Planning an item that has an order shouldn't suggest a change if the move is larger than Lot Accumulation Period, but lower than Dampener Period.
Steps to reproduce
- Create an item with Lot Accumulation Period set to 1W and Dampener Period set to 1M.
- Create a sales order with requested delivery date 1W into the future.
- Plan the item and create a purchase order.
- Change requested delivery date to 1M into the future.
- Plan the item again, and see the suggested line(s) to change the delivery date.
Additional context
I believe this was a bug from the beginning. After that the tooltips and documentation has been based on the actual behaviour, not the intended behaviour.
I can't see that any of the documentation explains why the Dampener Period can't be larger than the Lot Accumulation Period.
The documenation at https://learn.microsoft.com/en-us/dynamics365/business-central/design-details-planning-parameters needs to be updated/simplified when the code is changed.
If this bug isn't accepted the comment in the code should be updated instead.
I will provide a fix for a bug
Describe the issue
It doesn't make sense that Dampener Period can't be larger than Lot Accumulation Period when planning Lot-for-Lot.
Much more reasonable would be that a minimum of the lot accumulation period is used, and a larger time period can be set by using Dampener Period.
The comment in the code suggests that this was the intended use, and it's a bug that it doesn't work like that. (See

CalcDampenerDays()in PlanningGetParameters.Codeunit.al)Expected behavior
Planning an item that has an order shouldn't suggest a change if the move is larger than Lot Accumulation Period, but lower than Dampener Period.
Steps to reproduce
Additional context
I believe this was a bug from the beginning. After that the tooltips and documentation has been based on the actual behaviour, not the intended behaviour.
I can't see that any of the documentation explains why the Dampener Period can't be larger than the Lot Accumulation Period.
The documenation at https://learn.microsoft.com/en-us/dynamics365/business-central/design-details-planning-parameters needs to be updated/simplified when the code is changed.
If this bug isn't accepted the comment in the code should be updated instead.
I will provide a fix for a bug