1. Enrollment don/ with following details - /

Effective Date -02/01/2009
DateTimeStamp - 03/03/2009
Termination Date - NULL
Associated Rate - R1 ($15)

2. Change the employee's class
With this rate R1 gets terminated and employee gets rate R2

Effective date of class change - 10/01/2016
Associated rate after the class change - R2 ($50)

Hence, RateChanges_log entries will be like -

02/01/2009 to 09/30/2016 - R1
10/01/2016 to NULL - R2

20th Dec 2016 - changes done in classed

20th Dec 2016 - invoice for Dec 2016 is fetched
(earlier invoices till Dec 2016 have been generated)

Adjustment details are fetched as per expectation but in billing details section 0 cost is being displayed for this ongoing enrollment whereas it should have displayed the R2 cost i.e 50$. Please refer attached screen shot