Apex will automatically move Dispatch Loads to future times when the Dispatch Order is updated. When this happens, you gain a picture of what your schedule looks like now. However, you lose the picture of what Dispatch Loads are late.
It would be nice to retain the original time, while also showing the more realistic time. This will provide both benefits - knowing which Dispatch Loads are late, but showing what the affects of being late has had on the schedule.