[shados]

That is simply not true. There are many factors influencing your credit score in the US, however as far as credit utilization goes, the lower the better. Your credit score is based on how much unused credit you have.

Your bank may not want to increase the limit on a credit card you never use, but that's about it. If you want a high credit score, get the highest limit you can, always pay it off, keep it around for a long time, and never miss a payment for over a month. You also want multiple lenders (a single credit card won't, or multiple ones from the same bank won't cut it).