On-Demand Billing. (The Greatest Flexibility) Not sure of the host count? Does the number of hosts vary during the month? Just running tests for a few days? This option is for you. You will be billed each month based on an hourly rate for the number of hosts connected to RPM service for any portion of an hour. For example, if your application connects 10 hosts for 4 days (10x96 hours=960) and then later in the month it connects 6 hosts for 24 hours (6x24=144), you will be billed for 1104 hours at the hourly rate of the RPM level you choose. You will be billed up-front a minimum charge equal to one host for a month (at the Annual Plan rate). This up-front fee will be credited toward your monthly usage charge.