This creates problems. However, there are differences between the two representations. Either property satisfies definition. For state based encodings you must permanently decide the quantum of each state. Once you've done so showing that an action occurs over an interval becomes tedious and adds a tremendous amount of constraints.
Smaller quanta allow for better accuracy but severely increase the difficulty.
If you can split an action so that it can be partially satisfied at different points in the plan than there is an infinite number of ways this can be done. One planner that does look at splitting up a task is Zeno. Least Commitment can be good and bad. If you make up your mind too fast than more backtracking is required, but if you don't do it at all there are too many possibilities. For example, if you plan out the next 10 years of your life you are in trouble.