Changing subscription costs?

When a system’s subscription cost is about to change, how

does it work?



If, for example, a system’s cost is going from $100 to $200 on

March 15, and I subscribe today, the 13th, will I be at the $100

rate until April 15th, and at the $200 rate thereafter? Or will I

be at the $100 rate for just the next two days and at the $200

rate for the subsequent 28 days in the month?