In most cases, when a timeoff balance is wrong it is caused by proration.
When you enter an employees timeoff allowances into Natural HR, you should enter the full years allowance - do NOT prorate their allowance to account for starting or finishing mid year.
Holiday year begins 1st January and Bob starts on 1st July and his full "normal" year entitlement is 28 days. You should enter 28 days as his entitlement - the system will know he has started mid year and will prorate his allowance accordingly.
If you enter 14 days, the system will then prorate this to ~7 days which will be incorrect.
The other thing to be mindful of is contract end date - if you have set a contract end date, the system will also use that when prorating allowances if it falls in the current holiday year.
Bob's contract end date is set to 30th September - you should still enter 28 days as his entitlement and the system will prorate this again.
If you were to enter 7 days in this instance, the system will then prorate this to ~3.5 days which will, again, be incorrect.
Note on part time workers
If you have a part time employee then the system will still prorate their allowances using their start and end date BUT not based on their working days hence you need to calculate their normal annual entitlement.
All full time employees are entitled to 20 days - Joan works 2 days per week so is entitled to 8 days. You should enter 8 days - if you enter 20 days the system will not prorate this to allow for her working less than "normal" hours.
Proration currently only occurs for start and end date - not for working days / hours.