Intuit screwed the pooch on this one.
Check one of your pay stubs against what the IRS sent you in the mail for withholding rates or go read them online:
Intuit doesn't have anyone smart enough to know the difference between "At least" and "But less than".
This Quickbooks page
regard "Pay your employees and payroll taxes correctly, with less time, effort and risk of error."
I guess they exclude themselves with the 'risk of error' part.
Just Call Me, Fed Up with Intuit