The user of-course can already implicitly work out this information from comparing the fee-rate with the actual fee.

I think that it would be useful for people not wanting to do this arithmetic in their head.

if (CBitcoinAddress(rec->address).IsValid())
            {
                CTxDestination address = CBitcoinAddress(rec->address).Get();
                if (wallet->mapAddressBook.count(address))
                {
                    strHTML += "<b>" + tr("From") + ":</b> " + tr("unknown") + "<br>";
                    strHTML += "<b>" + tr("To") + ":</b> ";
                    strHTML += GUIUtil::HtmlEscape(rec->address);
                    QString addressOwned = (::IsMine(*wallet, address) == ISMINE_SPENDABLE) ? tr("own address") : tr("watch-only");
                    if (!wallet->mapAddressBook[address].name.empty())
                        strHTML += " (" + addressOwned + ", " + tr("label") + ": " + GUIUtil::HtmlEscape(wallet->mapAddressBook[address].name) + ")";
                    else
                        strHTML += " (" + addressOwned + ")";
                    strHTML += "<br>";
                }
            }
        }
    }
    
    
    
    if (wtx.mapValue.count("to") && !wtx.mapValue["to"].empty())
    {
        
        std::string strAddress = wtx.mapValue["to"];
        strHTML += "<b>" + tr("To") + ":</b> ";
        CTxDestination dest = CBitcoinAddress(strAddress).Get();
        if (wallet->mapAddressBook.count(dest) && !wallet->mapAddressBook[dest].name.empty())
            strHTML += GUIUtil::HtmlEscape(wallet->mapAddressBook[dest].name) + " ";
        strHTML += GUIUtil::HtmlEscape(strAddress) + "<br>";