The rebate itself does not have to be disclosed to the seller.

Also I don’t recommend to put it in the offer at all. When I have the buyer sign the RPA and associated docs to be delivered to the listing agent, I have the addendum that specifies the rebate between myself and the buyer also signed at that time. It goes into the file that I carry on the transaction. In the offer you can specify the credit back to the buyer simply for NRCC and RCC. You also submit a CBC that reduces your commission. From the sellers standpoint it is a wash.

Because of the way I structure the rebate what does need authorization from the seller is that the seller will be crediting the buyer directly with X$.

You will note this is also a handy way for the buyer to maximize the return. The credit back is used for recurring/non recurring closing costs and is not any different then any other credit back from a seller to a buyer in a real estate transaction. At the same time you have specified in the CBC form to the listing agent a reduction in your commission. Thus you the agent/broker only receive the reduced commission. Your client receives the rebate, it is all done in a well documented manner.

This should be done at the very beginning of the transaction so the lender for your buyer is aware of a credit back to your buyer from the seller. Escrow is also made aware so the document trail has everything correct numbers wise.