Unfortunately the plugin does not record the actual amount that was paid in fees to the blockchain network. The plugin only records the fees that the user sees, which should be more than the actual fee. The reason is that not all wallets report back the actual fees paid and therefore the transaction DB schema and coin adapter API are not designed to hold that information.
If you know how much your wallet pays in fees in a typical transaction, you can calculate this. Go to the admin dashboard and you will see sums of fees paid and transaction counts for the last day, week, month, and year.
For example, say that there have been 10 BTC withdrawals, and the sum of fees paid was 0.00500000 using CoinPayments. We know that CoinPayments uses a fee of 0.00040000 (or 40k satoshis) per BTC withdrawal. Therefore, the fees that remain with your site are 0.00500000 – 10*0.0004 = 0.001 BTC.
On the other hand, the fees that you see paid for internal transfers is accurate, as shown in the admin dashboard. All the fees paid for internal transfers are yours since you don’t pay a network fee for those.
The same goes for full node wallets, you just need the
txfee value that you use in your
.conf file to do the same calculation.
Hope this helps. Let me know if you have any more questions about this.