BDC and BAPI MM module

Hi ,

I have program where they are updating the PO new price in the T-code MEK1 and calling BAPI  BAPI_GOODSMVT_CREATE

Example : PO price in ME23N is 100.

1. sometimes the price wont be same so using Z-program they calling the BDC to update the value in MEK1 price let us assume 120.

2. Calling the BAPI BAPI_GOODSMVT_CREATE to create the 101 movement type (not passing the price)

In most cases price 120 got updated but rarely its picking the value from PO price .

so its difficult to re create the scenario.

requirement : All the time the user new price via z-program should be updated in the 101 movement type not the PO price maintained .

please suggest ..

regards,

guru