Calculating Whole Month Threshold Proration

When using the Use Whole Month Threshold proration calculation, Billing Central calculates how many whole months are in the partial period, then:

  • If the remainder is 16 days or more, it is charged as a whole month.
  • If the remainder is less than 16 days, no charge is made for those days.

The formula used to calculate the prorated value for the partial period is:

Sales Price * ((W+R)/Z)

where:

  • W is the number of days in the partial period / 30.4 rounded down to a whole number. This calculates the number of whole months in the partial period.
  • R is either of the following:
    1 if the remainder from W is equal to or greater than 16
    0 if the remainder from W is less than 16
  • Z is the number of months in the full period.
Note:

If some lines on a contract have daily (+/-000D) or weekly charge terms (WB/WE with or without an adjustment), Billing Central uses the Actual Days calculation method to calculate prorated values on those lines, even if the proration policy assigned to the contract uses the Use Whole Month Threshold calculation method.

Example 1

Line Start Date

Line End Date

Charge Term

Line Sales Price

First Charge Period

Final Charge Period

Sun, March 19, 2017 Fri, April 21, 2017 QB $90

March 19 to March 31 = 13 days

W = 13/30.4 rounded down to a whole number = 0 with 13 remainder

13 < 16 so R = 0

Jan 1 to March 31 = 3 months

$90 * (0/3) = $0

April 1 to April 21 = 21 days

W = 21/30.4 rounded down to a whole number = 0 with 21 remainder

21 > 16 so R = 1

April 1 to June 30 = 3 months

$90 * (1/3) = $30

Illustration

Example 2

Line Start Date

Line End Date

Charge Term

Line Sales Price

First Charge Period

Final Charge Period

Sun, Aug 20, 2017 Fri, May 18, 2018 YB $120

Aug 20 to Dec 31 = 134 days

W = 134/30.4 rounded down to a whole number = 4 with 12.4 remainder

12.4 < 16 so R = 0

Jan 1 to Dec 31 = 12 months

$120 * (4/12) = $40

Jan 1 to May 18 = 138 days

W = 138/30.4 rounded down to a whole number = 4 with 16.4 remainder

16.4 > 16 so R = 1

Jan 1 to Dec 31 = 12 months

$120 * (5/12) = $50

 

Illustration