BOM Display with respect to Change

Sir,

There is a scenario wherein a Part no A is deleted from a BOM on 15.04.2009. A New part no B is added B is added on the same date.

What will be the ouput of CS12 on 14.04.2009 - will the Old Part no A be displayed or B will be displayed?. What is the Valid from date in the input of CS12?.

What will be output of CS03 on 14.04.2009 - will the Old Part no A be displayed or B will be displayed?. What is Valid From and Valid To date in the input of CS03?.

Can anyone explain me on this topic?.

Regards,

R. Vijayakumar