KANSAS CITY, Mo. (AP) _ Sprint Corp. is launching a new plan to address wireless customers' criticisms about how much they're charged for extra time they spend on cell phones.

The plan, introduced Monday, allows customers who exceed their 300 so-called ``anytime minutes'' to pay $2.50 for additional 25- to 50-minute blocks.

Currently, many wireless customers sign one- or two-year contracts in which they pay a set amount each month to receive a block of anytime minutes and unlimited _ or nearly unlimited _ night and weekend minutes. But customers who use up their anytime minutes may be charged up to 50 cents a minute for additional time; Sprint customers pay up to 40 cents a minute for more time.

Under Sprint's new plan, customers pay $35 and get 300 anytime minutes, plus unlimited night and weekend minutes. Customers who use extra anytime minutes will pay $2.50 for 25-minute blocks, until they reach about 650 minutes. Then, that $2.50 will buy them 50-minute blocks _ or about 5 cents a minute for those who use up the entire block. Once customers have used 1,250 minutes, they must pay 7 cents a minute for more time.

Len Lauer, president and chief operating officer of the Overland Park, Kan.-based telecommunications firm, said the plan is tailored for people who occasionally use more than 300 anytime minutes and want some flexibility, not for those who use a lot of minutes or can predict how many minutes they'll use each month.

Forrester Research analyst Charles Golvin said the plan could be appealing to consumers concerned about exceeding their allotted minutes, but added that it may be too complex to market. Sprint plans to begin advertising the plan next Monday.

``It's an idea that certainly can work; however, the test will be in the execution,'' Golvin said. ``It's one thing to say, `Here's the problem and here's our solution to it.' The real test is: Will consumers be able to discern that this solution really does address the problem?''

Sprint has about 21.3 million U.S. wireless customers.

Sprint also introduced a new 14-day satisfaction guarantee, which allows people to cancel their contracts and return their phones within two weeks of activation. Another new policy allows customers to change their contract within three months without incurring penalties.