How will I be charged if I upgrade or downgrade?
There is no extra fee for upgrading, or downgrading, a package. The only difference is in the price between your old package and the new, which will be reflected in the new Activation Letter sent when a package is a changed. You may upgrade or downgrade at anytime, you do not have to do it on a certain date however you must maintain an upgraded or downgraded package for a minimum of one month. When a package is changed The Server Center simply pro-rates out the old package and applies any credits that may be remaining to the newly changed package.