Hi, just wondering about the order of fee collection in case of a revert / not enough fund case scenario:

• xCheque(...) fn transfer the fee before transfering the amount to the dst contract
• xChai(...) fn transfer the fee after transfering the amount to the dst contract

Does it technically matters at some point?

+ exitChai() questions

• The fn collect the fee in chai, why not collecting in dai ? My guess is that It would introduce a SafeMath.sol and it's a burden you want to avoid ?
• The fn use dai.balanceOf(address(this)) to avoid computing the amount passed in dai but is it safe ? Why not calling chai.dai(sender) beforehand and use chai.draw() instead ?