Inflation is not necessarily inflation, there is different type's of inflation. A few of us e.g. have commented in the past how flawed the official way of measuring inflation is.
Generally the government manipulate it to suit their own purposes, rather than provide a reasonable measure of inflation for the average person. Student loan interest is based on RPI for example so they have an incentive to push it up a notch, while trying to manipulate CPI to reduce it and make it look like they are doing a great job on the economy.
The best thing you can do is use one of those calculators to work out your personal inflation based on your own basket of goods.