(1) Also in cases in which commission agents execute the commission by way of self-dealing, they are to charge the principal the more favourable price, if, by the exercise of due care, they were able to execute the commission at a more favourable price than the one resulting under section 400.
(2) If, before the notice of execution is transmitted, the commission agent has, by reason of the commission given to them, concluded a transaction with a third party on the stock exchange or on the market, they will not be permitted to charge the principal a less favourable price than the contractual price.