Hi Sarah38,
Thanks for posting and welcome to the Community Forum.
I understand the need to have all reports agree with the month-to-date data in the Entitlement Balance Summary report. If this report does not agree with the YTD reports, I would suggest comparing the values of this report to the Pay History (Card file > Cards List > Employee tab > Blue arrow next to employee > Payroll detail > Pay history) of the employee month-by-month. This will narrow down the months when the issue started. After identifying the month when the issue started, we could correct it. I would suggest reading through this article Adjusting leave entitlements, this has a lot of information about how the entitlement works in the application.
Let us know if you require any further assistance. We're happy to help.
Cheers,
Genreve