Hi All,
I believe I have found some bugs this week in the MRP date calculations for PO suggestions.
I’ve reported the issues to Epicor but wanted to post here too as I am interested to know if anyone else is being impacted by these issues and perhaps garner support for Epicor to implement a fix.
In summary, I have determined that all supplier calendars MUST be 7-day calendars in order for MRP to calculate the dates correctly on PO suggestions which are NOT linked to a demand record.
Additionally, the supplier calendar and site calendar MUST have the same number of working days in a week in order for the “orderby” and “duedate” to calculate correctly when running MRP with “Allow Historical Dates” Un-checked.
This is crippling for us as the only way to implement workarounds for both these issues is to have the site calendar and supplier calendar both as 7-day weeks
We rely on the site calendar to default production job values so setting it to 7-day is not an option for us.
I’ll update here with the problem number when/if the issue is accepted by Epicor. I’m pretty sure I’ve seen a few issues raised here which could be explained by these problems so wanted to put out a PSA and gauge how widespread the impact might be.
Details of bugs below
Allow Historical Dates with 5 day supplier calendar Bug:
- When “Allow Historical Dates” is unchecked, the MRP will make a calculation for every demand record to determine if the resulting “OrderBy” date will be in the past
- The following calculation is done for each demand record
- Demand Due Date – LeadTime = OrderByDate
- IF OrderByDate < Today THEN Historical = True
- If historical = true then the MRP will ignore the demand record and move onto the next demand record until it finds a due date where the resulting OrderByDate is not in the past.
- The issue here is that the calculation of the “OrderByDate” within the operation that determines if a suggestion is historical is different to how the actual “OrderByDate” is calculated when the PO suggestion is created.
- The difference between these calculations comes down to the calendars used. The calculation that determines if a due date will land in the past ALWAYS uses calendar days. Whereas the actual OrderByDate on the suggestion Is calculated using the supplier calendar
- This results in PO suggestions with OrderBy dates in the past and DueDates which are not able to be met.
- Functionally this means to work around this issue, all supplier calendars MUST be 7 day calendars in order to get suggestions with orderby & due dates that can be met.
Test Examples
| PartNum | ABC123 |
|---|---|
| Lead Time | 120 |
| Supplier Cal | 5 Day |
| Site Cal | 5 Day |
| MRP Run Date | 01/08/2024 |
| Demand Date | 1/12/2024 |
| PO Sug DueDate | 1/12/2024 |
| PO Sug OrderBy | 13/06/2024 |
| PartNum | ABC123 |
|---|---|
| Lead Time | 120 |
| Supplier Cal | 7 Day |
| Site Cal | 5 Day |
| MRP Run Date | 01/08/2024 |
| Demand Date | 1/12/2024 |
| PO Sug DueDate | 29/11/2024 |
| PO Sug OrderBy | 01/08/2024 |
Differing Supplier & Site Calendar Bug:
- When a suggestion is made to bring stock up to minimum, but there is no demand record to pull a due date from the MRP engine calculates the due date as : (Today + Lead Time = DueDate)
- Then when the PO suggestion is actually created the “OrderByDate” is calculated as : (DueDate – Lead Time = OrderByDate)
- The issue again is the calendars used for each of these calculations. The duedate calculation will always use the site calendar whereas the orderbydate calculation will always use the supplier calendar.
- This means that if your supplier calendar and site calendar don’t have the same number of working days each week then you will get purchase suggestions either with DueDates that can’t be met and OrderByDates in the past, or DueDates further out than expected and OrderByDates perpetually in the future.
- Functionally this means to work around this issue all supplier calendars must have the same number of working days as site calendars
- This combined with the historical dates issue means that all supplier and site calendars MUST be 7-day calendars for duedates and orderby dates to calculate correctly.
Test Examples
| PartNum | ABC123 |
|---|---|
| Lead Time | 20 |
| Supplier Cal | 7 Day |
| Site Cal | 5 Day |
| MRP Run Date | 01/08/2024 |
| PO DueDate | 29/08/2024 |
| DueDate Calc | 5 Day |
| PO OrderByDate | 09/08/2024 |
| OrderBy Calc | 7 Day |
| PartNum | ABC123 |
|---|---|
| Lead Time | 20 |
| Supplier Cal | 7 Day |
| Site Cal | 7 Day |
| MRP Run Date | 01/08/2024 |
| PO DueDate | 21/08/2024 |
| DueDate Calc | 7 Day |
| PO OrderByDate | 01/08/2024 |
| OrderBy Calc | 7 Day |
| PartNum | ABC123 |
|---|---|
| Lead Time | 20 |
| Supplier Cal | 5 Day |
| Site Cal | 5 Day |
| MRP Run Date | 01/08/2024 |
| PO DueDate | 29/08/2024 |
| DueDate Calc | 5 Day |
| PO OrderByDate | 01/08/2024 |
| OrderBy Calc | 5 Day |