The above video covers the Calculate Fixed Percent Deduction Based on Earnings Subject YTD checkbox. This feature is found in the Payroll module for Microsoft Dynamics SL, formerly known as Microsoft Solomon. The checkbox is located at the bottom of the Deduction screen, from the Maintenance section of the Payroll module.
When this checkbox is selected, it lets the deduction be calculated on the remaining max year to date subject base, instead of being limited by the current rate multiplied by the fixed percent rate. This feature is useful if the rate decreased during the year, and an employee had not reached their max year to date subject base limit.