Cash forwards are interest free, so much less predatory. What they seem to be doing though is taking all the "excess income" and "saving" it to their accounts,

Cash forwards are interest free, so much less predatory. What they seem to be doing though is taking all the "excess income" and "saving" it to their accounts, which they'll give you a portion of the interest they earn on. They've obviously worked out the math that after a certain level, "topping up" your account can even be done within the interest earned.