Planned order - basic scheduling & Production order Lead time scheduling

Hi,

Lets say I have run MRP for a material with scheduling key 1 (Basic dates scheduling).

the planned order is created considering the in house production time in MRP which is quantity independent and approximate.

But when i convert the planned order to production order and relaease it... the system schedules the order considering the times in routing.

There will obviously be differences betwwen the dates determined earlier thru basic scheduling and the dates determined now from the routing and this may lead to extension of the delivery date. How does SAP accomodate this?.

regards,

Ashok