Discount condition type not appearing in sales order but in invoice

Hi,

I have two discount condition types (MPDI,ZSDI) in my pricing procedure,at the time of sales order creation one discount condition is not appearing.

On analyzing the condition type MPDI,system throws message "Access not been executed due to previous access",what would be the reason.

In the billing ,i could see the condition type appearing.I have checked this,but i could not understand why it is happening.Even the condition catergory of condition is empty not L.

Also please find the screen shots below,

Pradeep