Where, in an action by a broker for commissions for procuring a purchaser of real estate the evidence showed that he was employed to procure a purchaser willing to pay $16,000, for a commission of whatever was obtained in excess of that sum, that he procured a purchaser willing to pay $16,500 on condition that the owner should pay two and one-half per cent. thereof to the purchaser's agent as compensation in the transaction, and that the owner refused to convey, an instruction that the broker could recover $500 and an instruction that he could recover the difference between $16,000 and the sum which the purchaser secured by him was willing to pay for the property, were inconsistent. Slayftack v. Wetzel (Mo. App. '09), 123 S. W. 982. Compare Sec. 307.