Your confirmed economy seating for commuting is only for a couple of events:
Travel to Japan from the U.S. for the beginning of training and afterwards back to the U.S.
Travel to Japan from the U.S. to start your contract.
Travel from Japan back to the U.S. to start your vacation, then back again when vacation is over.
Travel from Japan back to the U.S. at completion of your contract.
Anything on your off days each month is YOUR responsibility to buy ZED fares for. Business class ZED to/from Japan runs around $1,000 and is space available. Easier to go up through Alaska or something than straight to L.A., loads are pretty high these days, and business class (and first) are usually pretty booked and difficult to get on.
This was a bit of a surprise for me, as well. Most of the other contracts offer business class positive-space travel for those events.