Dimension Customers in Irvine, Other Areas to Have Lower Cable Bills : Service: The reductions, ranging from 60 cents to $2.54, are due to miscalculations of new rates.

Saying that it miscalculated the first time around, Dimension Cable Services is trimming the monthly bills of customers in Irvine and several other communities.

The reductions, which range from 60 cents to $2.54, apply to customers in parts of Tustin, Newport Beach and the El Toro Marine base.

Cable companies across the nation changed their rates Sept. 1 to comply with the federal Cable Act of 1992. Dimension realized last week, spokeswoman Susan Ritchie said Tuesday, that it had figured wrong.

The newly adjusted rates will be retroactive to Aug. 31, Ritchie said. Customers will see a change in their bills as of Dec. 1.

Customers in Dimension’s upgraded, 56-channel system will see $2.54 knocked off their bills. Basic service falls from $15.15 to $13.50, and Dimension service--which includes premium stations such as CNN, ESPN and USA--decreases from $8.10 to $7.21.

Customers in the older cable network, which has 40 channels, will see the basic service rate drop from $12.37 to $12. If they receive Dimension service, that charge will decrease from $7.73 to $7.50.

“We were given a short period of time to implement very complex federal rules, which were loaded with ambiguity,” said Mark Stuckey, general manager of the Newport Beach-based cable company. “When it came to applying these rules to a recently rebuilt cable system such as ours, there wasn’t much guidance.”

Dimension serves 42,000 customers in Orange County, of which 10,000 are in the upgraded cable network area. Dimension is owned by Times Mirror Co., parent company of the Los Angeles Times.