An experiment in understatement has earned Norwest Mortgage a raft of  potential business. 
The Des Moines-based lender pulled in more than 250 leads from a 4.5-  inch newspaper advertisement it ran for a few weeks in a Boston-area daily   this spring.   
  
The ad offered to evaluate consumers' credit as a way of determining  what kind of home they could afford. Executives at Norwest Mortgage Inc.,   which lends all over the country, chose a very modest start to see whether   customers would take to the approach.     
The results have been encouraging, said John R. Adam, a senior vice  president at the mortgage lender. 
  
People who call the advertisement's toll-free phone number have  demonstrated a firm interest in buying homes and hooking up with a lender,   he said.   
Norwest was introduced to the advertising program by PMI Group, one of  the mortgage insurers it uses when underwriting loans. The system takes   down callers' financial information, pulls a credit report electronically,   assesses borrowing ability, and forwards this information to the lender.     
On the basis of initial results, Norwest plans to expand the program  into New York, with ads in suburban publications and radio spots in   Manhattan.   
  
The company is also giving serious thought to a nationwide rollout using  advertisements on a regional basis, Mr. Adam said. 
Norwest is especially pleased that most of the callers are interested in  buying homes, not refinancing mortgages, Mr. Adam said. Callers also are   responding to the ad early in the homebuying process.   
As a result, Norwest is able to strengthen its ties to realty brokers by  referring callers to them, Mr. Adam said. "That's working very well." 
Norwest's acceptance of the program bodes well for PMI, the mortgage  insurer that offers it. 
  
"These are things that make our customers more successful, which in turn  earns us more business," said Tony Porter, vice president of marketing at   the Fairfax, Va., company.   
PMI contracts with an Atlanta telecommunications firm, Strategic  Solutions Group, for the system. Strategic Solutions charges a $5,000   start-up fee and $5.95 for every lead its system turns up.