Professionals real estate agent Shane Brockelbank could not comment on the earlier sale as another company handled that, but said in the second sale the buyers were fully aware the house had sold for $440,000 only a short time before.
He said they received two or three offers around the same price, which indicated $510,000 was the property's correct market value.
It was possible the owner in the earlier sale received offers around that price, but could have chosen the lower offer of $440,000 because it might have been unconditional.
"If you're a first-home buyer and you're trying to buy a house, it does go to show if you can, be an unconditional buyer. Sometimes you can buy a little cheaper than people that have those conditions," he said.
When the house was marketed the second time around, Brockelbank organised staging furniture to be used in the house, which he said could sometimes add $20-30,000 to the value, with a cost of up to $4000 depending on how "elite" the staging company is.
"The staging would have made a massive difference on selling that property . . . when you're selling a vacant home, people will drift in and out of the home and they don't really understand the flow of the home and how it works."
Putting furniture in could help them imagine themselves in the house and see how the flow worked.
Other factors that could have helped with the price jump were new photographs and a video, and listing the property on more websites.
Brockelbank said a fast jump in price was not unusual for places like Naenae, Stokes Valley and Wainuiomata, all of which had seen plenty of growth in prices.
"The gains over the last two years are almost 40 per cent . . . [they are] all in a pretty competitive environment.
"I guess if you do things well and you advertise well and stage the home and present it well, you should get a good result."
The house has a current rateable value of $370,000.
