If you discover that a co-worker or yourself have too many banked hours or too few, the first thing you should check is whether you have used an abscence type that is not properly setup. In general this could mean that you have either used an abscence type that has added to your banked hours when it should not have. For instance sick leave or "time off in-lieu" that has not been checked to substract from banked hours or to add to banked hours might lead to significant discrepancies in banked hours.
Once you have made the necessary adjustments to the abscence types, these will have reotractive effect on the hours balance, automatically adjusting the hours balance to the correct amount.
A common mistake when facing big discrepancies in the banked hours balance is that the schedule has not been set up properly. For instance, a new employee starts logging hours, but no schedule has been assigned, then this will lead to Moment adding all hours worked as banked hours.
In order to set this up properly, you have to go to co-workers > choose the co-worker' > settings and then click "schedule"
Set up a schedule that properly covers the co-workers employment period. Once this has been defined, it will retroactively affect the hours balance, adjusting and reducing the amount of banked hours that the employee has.
Event though it is fully feasible to do adjustments to the hours balance at the end of the month or at the end of the year, the main reason as to why this is not recommendable:
The problems occured in the first place because you didn't have proper routines for setting up schedules, didn't know how to do it or simply forgot. Adjusting the hours is just a stop-gap measure, it will not solve the issue that you have to set up proper routines about how hours should be registered and what types of absences are supposed to be used. If you don't set up schedules properly, it will on
By adjusting schedules and the absence types you limit the possibility for banked hours being wrong again.