A valuer who is retained for the purpose of making a valuation which will or may be used to determine or assess monetary compensation,\ \ \ \ \ shall not have the valuation fee agreed before the valuation contract is signed.\ \ \ \ \ can make payment of a fee contingent upon, or fix a fee as a percentage of, the amount of that compensation.\ \ \ \ \ may make payment of a fee contingent upon, or fix a fee as a percentage of, the amount of that compensation.\ \ \ \ \ shall not make payment of a fee contingent upon, or fix a fee as a percentage of, the amount of that compensation.