[RealJames]

My experience with interac is that they take a huge overhead off your salary from the place you're working, including a lot of your holidays.
If you do what they do, which is contact the schools and ask if they need subs, then you can easily cut out the greedy middleman.
It all depends on where they place you too, some places they have contracts with which force them to give certain benefits to the teachers, if they can avoid it and pocket it instead they will.
For example, don't expect to see a bonus when all your Japanese coworkers do.

Honestly, the jobs you can get are 100 times better if you look for them from Japan, and simply walk into the workplace with a resume in hand.