Credit Card Companies are always looking for a way to squeeze some extra money out of their customers.  Two Cycle billing is now used by some.  Have you looked at the terms of your credit card?

In past years credit card companies calculated interest on the average daily balance for the past ONE month.  With Two Cycle Billing, if there was a balance at the start of a month, then average daily balance is calculated over the past TWO months.  

To see an example of how this affects you, use this calculator