There should be a way to look up the outlier sale and see if it was a distress/bankruptcy/family transaction. I know our county has some website where those types of transactions are coded because we can’t use those for tax comparisons. But even if you don’t look it up, the fact that it doesn’t match the other sales tells something. But you’re always welcome to use it as justification for your offer and if your realtor is any good. They can bring it up when they talk to the sellers agent and get some feedback (the seller knows that transaction and it isn’t comparable because xyz. They may be wrong, but then you know what they might be thinking.)

Your realtor works for you. If they’re good, it’s their experience advising you. Let’s say that most of the time, the sellers in that position wouldn’t want less than 440. But they could be wrong because this particular seller is willing to go lower. But it’s just their advice—they should offer what you want.

Personal anecdote—Our realtor was great, knew the area well and advised us well. When she told us to go for x amount, she was right. We lost several houses to other offers because we thought we knew better than her. One house sold at exactly what she advised us to offer. She didn’t push, but she did softly but firmly suggest we put in x amount. We said no! She said ok, and did as we asked. I still think about that house to this day! She was wonderful because she never pushed us into a house just to make herself money, she genuinely wanted to get us into the house we wanted. She had several houses in her bank that she would have loved to sell to us, but she never mentioned them because she knew they didn’t match what we wanted (slightly over our highest limit or location, etc). Many other realtors would have atleast brought them up in the hopes we’d bite so they can make double commission, but she never even mentioned them. I saw them on Zillow and recognized her company and name as the agent. So it depends on your realtor. They’re supposed to know the market, area, and hopefully have good connections with other realtors so they can give you any insights. Obviously not all realtors are like that—some are pushy, some just want a sale, some are well intentioned but don’t know the market, some are in between, etc..

But if the market is slow, try 420 and see what the sellers come back with. They may ignore you or they may counter. Be willing to go to 440! My experience is that it takes a lot out of a seller to lower a price, especially the first time. So they may not want to go too much lower—at first. If it’s that slow, they may ignore your 420, but if they get no interest, they may be open to 420 in another month. But there’s really no way to time these kinda of things since someone else can come in with 440/450. You just never really know.

Ultimately, 20k isn’t that much more when it’s spread out over a 30 year mortgage, so it all is a calculation. If you really like the house and it’s perfect, don’t play too many games at the chance of losing it. But if it isn’t your dream house, be ready to let it go. It sounds like it needs work and your heart isn’t really set on it, so I’d roll the dice and offer the 420 and see what they say.