This Wellesley Street property in Weston has appeared on MLS Property Information Network under four different addresses since 2002. It recently sold for $10 million.

Like a fresh coat of paint, brokers are finding a new way to spruce up their lingering listings – by changing their addresses.

The tweak in an address can make a property that has lingered on the market for months – even years – appear as newly listed, drawing the attention of real estate agents and house hunters. But some industry observers say it’s a misleading tactic that skews market data, making a property appear as if it has only been on the market a short time.

“It’s exaggerated when the market gets more difficult. People try to do more creative things to attract buyers,” said Barry Nystedt, a Newton agent who is president of the National Association of Exclusive Buyer Agents.

Nystedt said experienced agents will do the research and uncover a home’s true cumulative days on market. Those with less experience, however, may be misled. And for unsophisticated buyers, it could provide an unclear picture of the market history and weaken their bargaining power if they want to make a purchase offer on a home.

A recent example of a residence marketed with more than one address is a Weston mansion that sold at the beginning of June for $10 million. The property, which includes a 20,000 square-foot main residence and a 4,500-square-foot guest house, appeared in MLS Property Information Network under four different addresses.

The property’s address is 316-320 Wellesley St., as recorded at the Middlesex South District Registry of Deeds. But the property, first listed in 2002, was marketed as 316, 316-20, 316-320 and, finally, 320 Wellesley St.

Part of the confusion may have arisen because several agents tried to sell the property. At different points, the estate was listed by various agents from Hammond Residential GMAC, ERA Boston Real Estate Group and William Raveis Real Estate & Home Services.

Kathy Krongel, an agent with Hammond Residential GMAC who eventually sold the property, said the confusion likely arose because there are two homes with different addresses on the 2.8-acre parcel. The 20,000 square-foot mansion is actually 320 Wellesley St.

Krongel listed it in September 2007 as 320 Wellesley St. “That’s my best guess,” said Krongel, in explaining why it was listed under multiple addresses.

Krongel said she can’t remember whether she knew the home had previously been listed with a different address.

“It’s been on and off the market Â… I don’t know the exact history,” she said.

And some agents are unintentionally entering a wrong address in MLS, resulting in what is essentially a data input error, explained Linda O’Connor, owner of RealPro Associates in Beverly. In the case of the Weston home, O’Connor said it likely wasn’t “a willful misinterpretation of misappropriation.”

“Each one of those agents probably thought they were putting the right information in,” she said.

Data Integrity ‘Challenge’

But others are clearly manipulating the system.

“Data integrity is a huge challenge for all of us,” O’Connor said.

Nelson Zide, senior vide president of Whitinsville-based ERA Key Realty Services, acknowledged that some agents get creative in marketing homes by altering the address.

“I hate to say it but I will admit I’ve done it,” he said.

Zide argues that sometimes it’s the best option for properties that previously weren’t marketed properly. The new listing agents get penalized by having a property with a lengthy history attached to it, even though they’ve started new marketing efforts, he explained.

Address adjustments started cropping up frequently about two years ago when the housing market started its downturn, according to Carolyn Chodat, a broker who is on the MLS PIN board of directors. Some agents would add a hyphen or purposefully misspell a street name of a property that had been re-listed multiple times, she said. Others would add a space in between the numbers of an address.

“It makes [the property] look fresher,” said Chodat, who owns Classic Properties, which has offices in Medway and Milford.

In response to complaints from brokers and agents, MLS PIN implemented a policy that prohibits falsifying address information, according to John Breault, director of customer support for the listing service. MLS PIN routinely monitors for such errors.

“Unless there’s some legitimate reason that the address is changed, that’s prohibited,” Breault said.

But that hasn’t stopped agents from twisting the information.

“It’s still something that crops up,” said Breault.

In Marshfield, a four-bedroom farmhouse was listed last year as 3 White Holland Drive and re-listed at the beginning of the year as 3 White Holland Road.

Betsy Hines, a Marshfield broker who is also on MLS PIN’s board, said she used to get “fooled” by such changes. But now she notices them.

“Everybody should be playing on equal footing,” said Hines.

Nystedt, president of Buyer Brokerage Realty, said one condominium complex that frequently is misrepresented in the MLS is Cabot Estates. The luxury condos located in Jamaica Plain often are listed as being in Brookline.

“I think they’re trying to attract buyers that are looking at Brookline condos that might not otherwise look at Jamaica Plain, so I think that what’s going on,” Nystedt said. “The values are higher in Brookline. It makes it look like probably a relative value when compared to other Brookline listings.”