Despite new credit-card law brings some relief, the problems still arise.

It’s known, credit-card holders mostly benefited from the landmark Credit Card Accountability, Responsibility and Disclosure Act that initially went into effect a year ago. However, some troubling trends that are emerging could mean higher costs for consumers.

So, as the study from the Pew Charitable Trusts' Safe Credit Cards Project revealed, now cardholders have to play a guessing game with rate increases on late payments, plus deal with the widespread use of other penalty interest rates and steep increases in cash-advance fees.

The study scrutinized all consumer credit cards offered online by the nation's 12 largest banks and 12 largest credit unions. Those account for more than 90% of outstanding credit cards in the US It compared results from similar studies in 2009 and 2008 to March 2010.

While card issuers disclose that penalty interest rates, which can double and even triple monthly payments, will be applied to payments 60 days or more late, they don't say by how much, the report found.

At least 94% of bank cards and 46% of credit-union cards noted that interest rates could go up as a penalty for late payments and other violations but nearly half failed to say what the actual penalty interest rate was or how high it could climb, the report says.

Pew urged the Federal Reserve to address that when it writes rules. He suggested card issuers be prohibited from charging penalty interest rates that could jump after the account is opened.

Card holders already know what Pew confirmed: Interest rates have shot up about 30% since December 2008.

Nevertheless, credit-card interest rates and fees still are generally lower on credit-union cards, averaging about 16%, than those issued by the big banks, which average 21%.

Late fees are still as ubiquitous as ever: 100% of bank cards charge them and 95% of credit unions do, and still cost about the same. Banks cards are still an average of $39 while credit unions upped theirs to $25 from $20.

Cash-advance fees, on the other hand, have risen at both banks and credit unions. Average rates on cash advances from bank cards rose 14%, to about 24% since July 2009, and average rates rose 16%, to 16% on credit-union cards.