Basically dual agent is no agent.
You should do everything from your side own. Dual agent CAN NOT disclose seller's ntention, interest or bottom line to you, buyer. If seller doesn't tell him to send a multiple counter to you, he won't tell you that. UNLESS you ask him: Is there any multiple offers situation on this house? Then he should tell you yes or no.
Dual agent 就是neutral agent。 拨一拨, 动一动。他不能有主动性的。