The start date of the shop order requisition is calculated from the lead time, but the shop order start and finish date is a result of the scheduling of its operations. There are several reasons why these could differs, for instance is the work center resource efficiency considered in the shop order scheduling, but does not affect the lead time. Typically tge shop order scheduling is much more "correct" than the more rough lead time. 

Hi,

Some additional comments to Björns comments...

Actually the lead time of the shop order requisitions are calculated like this:

Fixed Leadtime per Day + Variable Leadtime per Day * Mrp Planned Qty. And that can of course differ quite a lot from the manufacturing lead time in Inventory Part, which is based on Std Lot Size

It has been like that for many many years.

The manufacturing lead time of the part defined in Inventory Part is not so much used in manufacturing. On top of my head it is used by:

• Cumulative Lead Time calculation

• Setting of Unprotected Lead Time in DDMRP - gives Lead Time Category

• Leadtime Costing in Costing

• Availability Check when entering a CO Line (well this one is using expected lead time but they are often the same)

• Have I forgotten some functionality?

Cheers,

Mats