Hello Evan,
First check the Lot size Setting OMI4, If possible share screen shot .
What is setting maintained against the Scheduling ?
If your Requirement = Delivery date,In that case system consider your requirement date and deliver all material on same day
Ex. 30/01/2015 to 05/02/2015 In that case system deliver on 30/01/2015
Suppose in scheduling maintained like Period end = Delivery date, In that case system consider the period end date and deliver the material
Ex. 30/01/2015 to 05/02/2015 In that case system deliver on 05/02/2015
Please check and confirm the same
Regards
Umesh Mali