it will most likely have the rocket's computer as the primary chip to have KAL take control of the flight until the Sat's vizzy can take over
the advantages are its easy and simple so you dont have to delete the craft's vizzy. and you can deorbit the last stage to reduce orbital junk
The disadvantage is that after KAL finished, you have to switch to the sat. the AGs will also sometimes Trigger the program's abort if it uses the same KAL vizzy from another rocket (example is Nebula C2's abort AG-1)