Metro said it has been charging the wrong fares for years and now it’s giving refunds to a few of its riders.

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The Washington Metropolitan Area Transit Authority slipped in word of this snafu in the bottom of a weekend news release on fare hikes and new schedules. In small font, it called this a “technical correction to fare tables.”

What does that really mean?

Metro says about five percent of its riders were overcharged starting in 2015. According to the release, most of the charges were about a nickel off than what they were supposed to be.

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The agency is refunding anyone who paid more than two dollars extra by crediting registered SmarTrip cards. Cards will be credited sometime this summer, said Metro.

In this mess-up, Metro said it undercharged even more riders. That made the agency lose about $300,000. That’s just a tiny fraction of the agency’s budget, about 0.007 percent. The agency said undercharged riders will not owe money.