this is actually pretty common, but the majority of sources understand that by the time money has been deposited compared to the time that they are notified there will be fluctuations, that's the hit that they take, within reason..
next time around just deposit a few extra dollars to cover any fees.. just add maybe 10-15 or even 20$, this way if your source says anything you can tell him that you met him right down the middle.. you both absorb partial of the cost for convenience, an honorable source however will wave the fee!
it's always best to have open communication and contact the source and let them know when you're sending the finances, this way you're on the same page and they can make the collection by withdrawing from the market before there's a drop.