Header Condition changing to Item condition

Hi Gurus

I have a header condition ZXXX, Client want to change to item condition manual condition and for only ZOR order type only, for this abaper written rounite and working fine.

But if i made ZXXX header condition to item condition. Does system have any errors with existing open sales orders, deliveries. i have not made any changes in pricing procedure. Will anything changes in conditions of items and header level like subtotals, totals etcs...

Thanks

Ramki