Sorting as per Days Late & Days Early

One method is to enter this formula in column L and fill down and format the column with a custom format of ##" Days Early";##" Days Late" This will give the text that you currently have in column L but the actual values are numbers that are either positive or negative.

Formula:

=H2-K2+1

Click on a cell in the data and then click on the Data tab, Filter. All columns should now have filter buttons on the right side of the header cells. Click on the Variation column filter, click on Number Filters, choose Greater Than and enter 0. This filter will present you with all of the employees that returned early. If you had selected Less Than and entered 0 you would get all of the late returns.