[Ethic] Soft dollar disclosure

1/Suppose a brokerage house A provides a good quality research that can be used in managing clients’ accounts, and the brokerage A demands same transaction cost comparing with other brokerages. It’s necessary that we must disclose this “soft dollar” to clients?

2/ If this soft-dollar is costly (for exemple, this brokerage house A demands an higher transaction cost but gives a good quality research), must we obtain the permission of client before making a deal with brokerage house A?

I have these questions when I read the Standard III(A) Loyalty, Prudence and Care +the Standard VI© Referral Fees

Thanks in advance for your help!