Requistion Number Series , Purchase order No Series and Receipts series should be same

HI Friends,

We got a requirement from our business that Purchase Requisition Series , Purchase order Series, Receipt series should be same.

For Eg: Requistion # 10001

               Sno     Item     

               1          A item

               2          B Item

               3          C item

Purchase order # 20001

               Sno     item

               2          B item

               3          C item

Purchase order # 20002

               Sno     item

               1          A item

and so on for receipting

Can any body guide me the advantages and disadvantages for the same.

Ravi