Looks like flights from Japan to the USA fall under the "Piece pricing - Departing from the United States / Brazil" (even though you are traveling _to_ the United States. Sounds like you can do as many pieces as you want at the rates below (as long as 32kg and below).

# For flights departing from the United States, bags that weigh 23kg and above will be charged three times the rates shown in the table above.
# Any bag that weighs above 32kg requires advance arrangement. It may not be accepted as checked baggage and may have to be sent as cargo. Please contact your local SIA office prior to your travel.

LAX/SFO would be $84 * 3 = $252 for up to 32kg
EWR would be $94 * 3 = $282 for up to 32kg
JFK would be $149 * 3 = $447 for up to 32kg

And if you're over 32kg, you'll need to call and get the rate.