Hi bschool,
I'll do my best to help you with this. QuickBooks Desktop's T4 Summary report only provides information for This Calendar Year and Last Calendar Year, but there are other ways that you can find information that you're looking for. Other payroll reports can help you get the details that would show on the T4 Summary. A good place to start is the Employee Earnings Summary report. View my image below with mock data to see how the Employee Earnings Summary shows you the same information as the T4 Summary report in a different way. With the ability to make windows smaller, it's easy to put them side-by-side to compare.
There figures aren't all in the same order, but following the headings and categories for each one, you can see how they line up. If there's other information you need, feel free to check out more payroll reports to see what they can show you.
I hope that helps! Have a great weekend. :)