how make type planned order is deriving the suggested order date in unconstrained supply plan

Summary:

Hi Guru,

we are running the unconstrained plan and system is suggesting a planned make order with a suggested start date we cannot understand.

there is an sales order demand for an assembly '3MAG4-1-2‘ with a due date on 1/17/2026， so system is suggesting a work order with quantity 2801 with suggested due date on 1/17/2026.

the assembly has Fix LT=0.3333 and Variable LT=0.00138, and the processing lead time for this work order should be 0.3333+(0.00138*2801)=4.2, which means the suggested due date should be 1/12/2026， but the suggested start date was 1/10/2026， and we really want to know the reason why system is suggesting like this(we are using the calendar with 7 days a week and 6 working days/24 hours).