ByJohn S. McClenahen Even as Congress was passing and President Bush was signing a five-month extension of unemployment benefits, the U.S. Labor Department was assembling data showing that initial claims for jobless benefits fell last week. For the week ending Jan. 4, the seasonally adjusted figure for initial claims was 389,000, a decrease of 19,000 from the previous week's revised number of 408,000 and some 8,000 below the 397,000 initial claims that economists generally expected for last week. The department's four-week moving average for initial jobless claims is now at 406,000, down 13,750 from its previous mark of 419,750. "This index continues to send conflicting signs about the health of the labor market," observes Stan Shipley, a senior economist at Merrill Lynch & Co., New York. "Over the last six months, the average weekly change is about twice as volatile as was the case just three years ago." Bottom line: It will probably take several consecutive weeks of initial claims levels below 390,000 to have confidence that the U.S. job market has stabilized.