Hello there, @sassypantsdesign,
Thanks for letting me know that you've already figured out why there's a discrepancy on your reconciliation.
Since you don't have a Reconciliation Discrepancy option, it's possible you're using an outdated version of QuickBooks for Mac. Can I ask what version and year are you using? To help fix this, you can update the program. By doing so, it will help improve its functionality and fix known issues.
Here's how to update it:
For more information, you can check out this helpful article: Update QuickBooks Desktop for Mac.
Once updated, let's check if the Reconciliation Discrepancy report is now showing. If you want to learn more about this report, please see page 173 through this great article: User's Guide.
I'll be right here if you have other reconciliation concerns, @sassypantsdesign. Have an awesome day!