Sea Launch Orbital Geometry

We've probably discussed this before, but the
upcoming Sea Launch mission (set to begin once
the seas die down) has reintroduced an unanswered
question to my attention.

On this mission, the DMSL upper stage will perform
two burns to put 4.7 metric ton XM-3 into GTO.
The first burn will put the payload into a
180 x 9452 km x 0 deg parking orbit. The second
burn will begin 47 minutes after liftoff, at an
altitude of 4682 km, and will last three minutes.
The final planned orbit is 2466 x 35830 km x 0 deg.

Other commercial launchers typically perform upper
stage burns at either perigee or apogee. What is
different about Zenit 3/DMSL?

- Ed Kyle