The calculation period is the date range where a rate version is effective during the consumption period. For each rate version that is effective during the consumption period, a bill segment calculation period is created. A set of bill calculation lines is created for each calculation period.

A calculation period factor is determined for each calculation period. The calculation period factor is the ratio of calculation period days to normal days. If the consumption period factor is 1 (not applicable), then the calculation period factor is the ratio of calculation period days to consumption period days.

Example:

If the consumption period covers April 1 to April 30 and there was a new effective rate version as of April 21, there are two calculation periods.