If the plan tiers and carryover is set up in Payroll vs Time Off, go to Setup > (Codes) Payroll > Earning/Deduction Codes.  Find the accrual code and on the Employee tab, look at the Accrual Carry-over Date, in the grid below, scroll to the right and look at Max. Carryover.   These fields can affect an employee's available balance and carryover.  For example, perhaps you only allow 40 hours carry-over, or no hours at all.

If the plan tiers are set up in the attendance module, you can review the setup in Setup > (Codes) Time Off > Attendance Plans > Select employer.  If no plans are at the employer level, select Enterprise.  Detail the plan in question and go to Seniority Levels tab and review Max Carryover.  On the General Tab > Plan Year field will indicate if it is Fiscal, Annual or Anniversary.

If the above does not reveal the answer, I would suggest reaching out to Sage HRMS support.

Thank you!