When entering a Purchase Lead Time on Inventory Parts (Apps10 and Cloud) we are finding the dates presented confusing. For amendments to the Purchasing Lead Time, whether made in the field below or made on the SFPP Manufacturing Lead Time and then calculated by Calculate Purchase Lead Time, the dates we are getting are as follows ;
0 days - 31/03/25
1 day - 01/04/25 (Tuesday)
2 days - 01/04/25
3 days - 01/04/25 - shown below
4 days - 02/04/25
The Site Calendar is a 5 day working week calendar and the Primary Supplier also has a 5 day working week calendar, the same as the Site calendar.
This pattern is repeated the following week, with the same day (again a Tuesday) being presented for three different lead time days (8, 9,and 10 days).
Can someone explain this? How can zero lead time have a supply date of 31/03/25 and a 3 day lead time have a supply date of only one day later? There are no other lead-times in supply chain matrices.

Thanks.