Hi Abhimanyu,
In the overlapping scenario you describe, the restriction is related with the pegging (Pegging - SAP Library), a dynamic link between receipts and requirements, including orders of all BOM levels. This pegging is taken into account by the PP and DS strategy when you plan and schedule the orders.
This pegging constrain can be ignored in the PP and DS strategy definition, but is not recommended because it prevents you to schedule an order when the required inputs are not available to execute it.
A suitable solution for your scenario could be to define a lot size that force the orders to have a max size. In that way you will have more than one order to produce the same quantity. In the BOM level A, for example, you could use a max lot size of 100. Then you could schedule the order of the BOM level B after one order of the BOM level A, but before the total production is finished.
100 | 100 | BOM level A | |
100 | 100 | BOM level B | |
Hope it helps,
Jorge