Hi Kamia,
If you are following the instructions in the Optimization Exercise (this is Exercise 6 of our Basic Training Materials), then you will have first set up night/day time slices for each season (8 slices in total). If you then import hourly load data into these slices, you will find that you hourly data become highly "averaged" within each of the eight time slices - in other words, extrema like the minimum and maximum load will be suppressed.
LEAP internally calculates the peak load on the system using the annual energy requirement, the information in your system load curve, and the width (in hours) of each time slice. This means that LEAP will define peak load (and therefore the load factor) differently than the highest load hour which is visible in the 8760-data point Excel spreadsheet. You can view the peak load results in LEAP by selecting the result Transformation: Peak Power Requirements.
Hope this helps,
Taylor