What does this sentence mean?

[evenfriend]

I have received an offer from my credit card company--3.99% on new purchases until paid in full. I want to pay the $350 I owe them (at 7.99%) and then take advantage of the 3.99% offer, which is good for 2 more weeks.

But the letter I received contains this sentence:
"The application of payments and minimum finance charge may reduce the duration and benefit of any Introductory or Promotional rate offer."

What does that mean?

Thanks very much!

[Cathy]

They are saying two things. First, they are saying that they will post in your payments in a way that will benefit them the most. The most common example is applying payments to balances with lower APR's before the higher ones. Example: If you have a balance with the 3.9 intoductory rate and a balance with a higher rate, they will post all payments to the balance with the lower APR first until that is paid off, then start applying the payments to the balance with the higher APR, thereby making them more in interest charge profit. The second thing they are saying is in reference to the minimum finance charge according to your regular card agreement regardless of what your APR makes the interest come to. Example: Say you have a minimum finance charge of $2.00 according to your current card agreement, but the 3.9 APR (assuming that is your only balance) would otherwise make the interest calculation $0.50 for the given monthly billing cycle. They will charge you the $2.00 which in effect wipes out anything your 3.9 interest rate would otherwise save you. I hope this helps!