When a pass of CreateTransaction fails to select enough bitcoin to meet the nFeeNeeded the next pass through may select a far smaller collection of inputs.  Currently it will continue to use the old fee amount based on the larger set of inputs, which can cause a non-trivial over-payment.

This may be the cause of the behavior reported here: https://www.reddit.com/r/Bitcoin/comments/5ltw5n/bitcoin_core_v0131_sends_enormously_high_fee/

Long ago fixing this was tricky due to a catch-22 between signing the transaction and knowing how much fee was required.  But after #9465 the whole algorithm will run using a dummy signature, so when there is already a change output fixing up the fee after finding a sufficient transaction should be a matter of a ~2 line change.

{
    return (GetDebit(tx, ISMINE_ALL) > 0);
}
CAmount CWallet::GetDebit(const CTransaction& tx, const isminefilter& filter) const
{
    CAmount nDebit = 0;
    BOOST_FOREACH(const CTxIn& txin, tx.vin)
    {
        nDebit += GetDebit(txin, filter);
        if (!MoneyRange(nDebit))
            throw std::runtime_error(std::string(__func__) + ": value out of range");
    }
    return nDebit;
}
CAmount CWallet::GetCredit(const CTransaction& tx, const isminefilter& filter) const
{
    CAmount nCredit = 0;
    BOOST_FOREACH(const CTxOut& txout, tx.vout)
    {
        nCredit += GetCredit(txout, filter);
        if (!MoneyRange(nCredit))
            throw std::runtime_error(std::string(__func__) + ": value out of range");
    }
    return nCredit;
}
CAmount CWallet::GetChange(const CTransaction& tx) const
{
    CAmount nChange = 0;
    BOOST_FOREACH(const CTxOut& txout, tx.vout)