Conditional format time if less/equal to greater than a cell

In the attached file, the E column is the required hours that a student must be clocked in each week. I populate each week as the semester goes along, and what I want to have happen is this:

Looking at row 12. The student should be clocked in for 22 hours per week (cell E12). Cell F12 is greater than or equal to E12, so it should display as white fill/black font. Cell G12 is less than E12, so it should display black fill/white font. (We are printing to a black laserjet). My Excel version is 2010. I've tried conditional formatting, and I have had less than stellar results. I suspect it is the fact that I am dealing with time, rather than a normal numeric value.

Thanks in advance!