That's what happened to those of us that had January swaps going on.
I knew the $6 fee would be unsustainable, so I put my fee at $7....then, when both of the other January swaps put $6, I lowered to $6.50....turns out, I should have left it at the original fee.
Anyhoo...definitely give yourself some buffer on your fees because you want to make sure your delivery costs are covered! Good luck!