Unless things have changed (and more than happy to be corrected) the whole intent of AJV/X is that they, nor the contract agencies, do not address tax in any way, shape or form.
They give you a sum of money - what you do with it and any tax implications in the world are the SOLE RESPONSIBILITY of the contractor - you.
If you do not have Alien Residency you cannot pay Japanese tax; if you don't pay Japanese tax then you can't apply any bi-lateral tax agreements with other countries around the world.
There are Japanese contracts that pay Japanese tax - AJV/X has NEVER been one of those contracts.
Regards Crew taking out money - could be to put into sperannuation (401K or whatever the Yanks call it), a point of difference between the contract agencies.
Not all contracts are exactly the same. Contractor beware!
Cheers
