that would make about six million more low-income workers eligible for the e.i.t.c. but it would come at significant cost: at least $5.5 billion a year in new federal spending, according to the office of management and budget. questions about how to pay for an e.i.t.c. expansion are one reason bipartisan efforts have stalled in washington. but here in new york city, expanding the e.i.t.c. for some single workers is already underway. it's a pilot project called "paycheck plus," and here's how it works: the existing e.i.t.c. for workers without dependent children is being supplemented. participants who earn less than $30,000 a year are eligible for a bonus of up to $2,000, depending on how much they earned. gordon berlin's organization, m.d.r.c., is running the three- year demonstration project of "paycheck plus." 3,000 new yorkers are enrolled, along with a control group of workers not receiving the bonus. >> there's a lot of uncertainty about whether singles and men would respond in the same way that fathers and mothers of dependent children have responded. we don't k