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EngageIP follows a simple formula to this calculation, but that is only to get the final result. It is important to note that all calculations of periods are done in Months.
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In order to know the price per day the full period must be calculated, from which the number of days can be extracted. The full period is calculated based the package’s bill date, base time unit and frequency, as well as the start and end date of the proration period. The system figures out the next bill date of the package and uses this as the end of the full period. Next it looks at the start date of the prorate period and sets the start bill date as if it was available within the same month and year. Using these two dates, the start bill date and the next bill date, it figures out the number of full periods between both and compares it to the package’s base time unit and frequency. This gives the full number of periods the prorate period is within. If there is a monthly frequency greater than 1, then a calculation is performed to figure out how many periods are being occupied and converts them down into months. Once the number of full periods in months in determined, the previous bill date can be calculated based on the next bill date.
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