Two charts comparing long-distance rates and services that ran in last week's Washington Business contained several inaccuracies.

The chart information was compiled by the U.S. Public Interest Research Group based on information from the companies.

Some errors were caused by companies supplying inconsistent information, and in other cases, rate numbers were rounded off inaccurately, PIRG officials said.

The Washington Post obtained new figures from each company for the accompanying long-distance rate comparison chart. In addition, these are corrections to the PIRG's service comparison chart:

*AT&T -- To get the first two directory phone calls free, a minimum of two long-distance calls a month are required. After the free directory phone calls, additional calls are 60 cents, not 50 cents.

*CTI -- The number to open an account is (301) 363-2500.

*ITT -- Does offer directory assistance, for 45 cents per call.

MCI -- The local number to open an account is (800) 624-6240. Two directory-assistance phone calls are free, not three.

*SBS -- The correct number to open an account is (800) 235-2001, and SBS makes a routine residency and/or credit check. The weekend rate is valid all day Sunday and until 8 a.m. Monday.

*Western Union -- The number to open an account is (800) 527-5184. Western Union's minimum monthly charge is $10, and the billing increment is 60 seconds. Directory assistance is 50 cents a call after the first two free calls.