A flat-fee broker, who rebates a portion of the buyer's side commission is assuredly tempting. But as Chris pointed out, in one of the other three threads you started, sometimes (not always) you get what you pay for. If you feel comfortable, in a transaction as large as the one you described (which is $1,600,000) using someone less than a full-service agent/agency, then flat-fee/rebate service is for you. Many flat-fee/rebate agencies have you do the bulk of the work... schedule your own appointments, do your own negotiations, your own CMA, your own inspection... etc...
Not everyone feels comfortable with that business model.
If you are comfortable with all the negotiations, contracts, disclosures, scheduling of all the appointments and staying within your contingency periods then this probably is the way for you to go.
Wish you the best!