All of the above are right. ^^^ I have never seen this happen except in the case of short sales or foreclosures where the bank is paying the commission or if the property is a 'FSBO' (For Sale By Owner).
It is not typical to change the commission after the listing agreement is signed because the listing agreement is a contract that the seller has previously agreed to compensate the listing office prior to ever putting the property on the market. The office for the buyers agent gets a pre-determined amount of the gross commission. That amount is disclosed in the MLS. It is not supposed to change once the property is listed in the MLS per the contract each office has with the MLS.
So, when the commission changes that just shifts the party paying it, not the actual amount due. There is no "if we have the money we will pay it after closing clause". The way it works when the seller asks you to pay the commission portion toward your agent is that amount, whatever is agreed to, is added to your side of closing costs at the time of closing. It isn't an optional fee. If the listing figures don't add up, then either the house doesn't close or someone else brings in the funds. I would be very careful here.
Note: some sellers are under the impression that buyers' don't have closing costs to pay at closing. That is not true. If you are paying cash, then your closing costs are nominal, but if you are getting a mortgage, you have large costs due at closing too. Is it possible the listing agent hasn't explained all the costs you will have to pay? I have found that once the seller understands that both the buyer and seller are paying to close, you don't end up with the seller trying to shift the commission expense. The seller can only do this if you agree because the seller already signed their contract with the listing office. The seller has no way out of the fee now.
EDIT: Sounds like you have a seller's market in that neighborhood, is that true?
