Are there taxable benefits or any other payment, non-cash, that attracts EI premiums?

What version of Sage are you using?  If you calculated payroll using an old version of Sage (2019 or prior), you can get really funny EI insurable earnings results.

If using any version of Sage 50 other than 2022 or 2023 the numbers will not calculate the same as income tax rates, EI premiums and CPP contributions have all changed. 

Another alternative is that EI Insurable earnings is calculated based on the Employee's EI amount deducted.  When doing manual entries and/or adjustments as well, the EI Insurable is calculated based on a calculation of the EI entered and the internal EI deduction rate, not the Gross paid.

If the amount on the T4 tab of the employee ledger is incorrect, you can adjust it before printing the T4's.