BTC withdrawal transactions only:
Withdrawal fee depends on the following parameters:
-How many bytes do the transaction include. It is difficult to define mentioned parameter prior the withdrawal request.
-How fast should the transfer be performed. In FJ’s case it is equal approximately 20-25 minutes.
So these parameters are true because last week I got the full payment with no fees deducted at all, but this time I paid a fee of 0.00068837 BTC, which is almost 2 times more from what Cabalism13 paid. I have to admit that it was almost an instant transaction (if not confirmations), like always.
We can see that indeed fees are not equal and sometimes BTC withdrawals are even fee-free.
I have a suggestion: if the fee depends on time, then it would be great to have an option to choose a longer withdrawal time for no or smaller fee.