The values "Buy" and "Sell" are always the real amounts you have paid or received.
The "Fee" field is just a note and does not have an influence on the "Buy" or "Sell" value.
@Dario,
My Ledger Nano S wallet reports the total amount with a note that says "Includes Fees of X currency". So the total amount spent is the amount to report.
But Bitshares reports the amount spent AND a transaction fee in BTS. To get the quantities right, I have to subtract the spend from the currency account and also subtract the fee from the BTS account. So, the total "spend" is not the total amount spent! Plus, they send the transaction to OpenLedger, who takes more fees out to transfer it to wherever you are sending the money. From what I can tell, that amount is not reported anywhere, so the fee is the difference from what left BitShares and what arrived at the destination.
I also have a ETH based wallet (Exodus) that you have to have ETH in the wallet to send any of the other coins anywhere, because it subtracts the amount sent from the account and the fee separately in ETH, which accounts for part of the spend for the transaction.
And I have OmniWallet, which is a BTC based wallet. You have to have BTC in the wallet to send any of the other coins from the wallet, because it deducts the quantity sent from that account and some BTC from the BTC account.
With Bittrex, the spent amount includes the commission and the commission is reported separately, but it is part of the "spent" amount, so it's like the Ledger Nano S in that regard.
So, basically, sometimes the fee is just a note to tell the user how much it cost to do the transaction and so the fee is included in the "spend". Other times the fee really is a fee i
n addition to the amount reported in the "spend", so the fee has to be reported as a "spend" as well. Then there is the case of Bitshares/OpenLedger which just shows a "disappearance" that is another fee.
Are you saying you have a way for CT to handle these different use cases?