According to your data, the employee had 8 years of experience and should get 22 days (of some sort of Quota).
Is that a Quota that the employee was getting every year on a certain date?
Is it possible that the allowance upon termination was calculated at prorata, based on the number of days worked in the current year's quota validity period?
Is it a Quota that the employee gets only upon termination, and could it be reduced by the use of a certain type of Absences taken previously?
Do a Time Evaluation Test, with the "Display log" box checked, and try to see where the allowance gets generated and if that allowance is re-evaluated later in processing.