Blanket Purchase Orders release process

In the P43060 Blanket order release program, a user has the option to change the header branch/plant to something different than what was originally entered on the OB(Blanket).  This is extremely helpful for our purchasing department as they place large blanket orders that are then released to 16 different branches across the country.  Now as helpful as this process is in the P43060 release program, the release program is not as user friendly as the standard PO entry(P4311) program. 

 My question is why is the option to change the header branch/plant not offered when a blanket is released thru the P4311 program?  Currently during PO entry the header branch/plant from the OB is defaulted into the detail MCU field.  This then requires our buyers to remember to go back and change the branch on the detail line of the PO to reflect the correct branch.   I believe the P40216 is the release program that is used during PO entry and not the P43060.