Although it is possible that the listing agent may favor your offer since they stand to make a double commission. But Washington State has very strict statutes regarding agency duties and the listing agent has more than a fiduciary responsibility to the seller. They have a signed contract with the seller to represent the seller's best interests. The sellers best interests are nearly always maligned to the buyer's interests.
It is a bit challenging to represent a buyer against your own seller without someone feeling they got the short end of the deal. In the case of a listing agent the short end would almost certainly be the buyer. Personally I would be wary of any deal in which the principals or their agents participation is motivated by greed.
Most agents are honest and will work hard to do the right thing. Buyers are fortunate in that the services of selling real estate are almost always paid by the seller. The buyer therefore can enjoy the full representation of an agent who is bound by the same statutory and fiduciary duty to the buyer as is the listing agent to the seller at no cost to the buyer.
Right now this market is VERY hungry for clean move in ready homes. The in town move in ready homes from $225,000 to around $400,000 priced right, will sell fast and likely with multiple offers. Homes in rural or semi-rural areas with acreage from $350,000-$500,000 will see the same action. Buyers may have to offer on several homes before finally landing one. This is the nature of a seller's market.
Buyers can also look at homes that are not so picture perfect. I am not referring to a fixer, but a house that doesn't show as well. Maybe it has a lot of clutter. Maybe the yard is overgrown. These types of houses may in fact be fabulous homes that need just a touch of a new buyers TLC. These are not as likely to see multiple offers and bid up pricing because so many people can't look past superficial cosmetics. This can be the ticket to ride to quote the Beatles, for a buyer fed up with the seller's market.
Buyers should be patient and stick to a solid buyer's agent.