Washington state regulators have fined auto insurer Progressive over $150,000 for a second instance of charging improper premiums to policyholders within two years.

According to the office of Washington Insurance Commissioner Mike Kreidler, Progressive Classic Insurance Co. and Progressive Northwestern Insurance Co. used unapproved rates to calculate premiums for uninsured motorist bodily injury and property coverages during a seven-month period ending April 2006.

These unapproved rates, according to Mr. Kreidler's office, led to policyholders being overcharged or undercharged.

According to the order imposing the fines, Progressive undercharged 26,596 policyholders a total of $381,488 while 28,603 policyholders were overcharged by a total of $341,645. Progressive has acknowledged the error and refunded the overcharged premiums.

This latest incident is the second for Progressive, which was fined $10,000 for similar infractions in 2005, with half of that amount suspended on the condition that no other violations occur during a two-year period. The company has been ordered to pay the $5,000 that had been suspended.

The current fines against Progressive include a $100,000 fine for the new violations, with half of that now suspended on the condition that no new violations occur within two years.

Commissioner Kreidler ordered another member of the Progressive group, Progressive Max Insurance Co., to pay a $1,000 fine for using unapproved rates to calculate premiums for 614 policies issued during a six-month period ending March 2006.

Those infractions in turn violated terms of a suspended fine stemming from an earlier case also involving violations with unapproved rates affecting more than 760 policies. The fine in that case was $190,732 with half suspended on conditions of no additional violations. The company was ordered to pay that suspended part of the fine, which equates to $95,366.

In total, Mr. Kreidler's office said, the fines add up to $151,366.

For its part, Progressive acknowledged the error.

“Our intent is to always charge our customers the most accurate premium possible, but unfortunately, mistakes were made,” said Cristy Cote, a spokesperson for the company, in a statement.

The company added, “When we discovered the errors, we immediately made the Office of the Insurance Commissioner aware of them, took steps to correct them and made our customers whole. The average refund to those customers who were mistakenly overcharged was about $12. We are sorry for the errors and for any inconvenience we caused.”