Here, we investigate how much it modifies the emission profile if the time step of the simulation of diffusion (and relaxation transitions) is reduced. The influence of the diffusion on the fluorescent profile increases with the diffusion constant, the degree of photobleaching, and the length of the simulation. Accordingly, to study the “worst case,” we used and for the laser power and the photobleaching cross-section, respectively, since, among those presented in this paper, this is the setting that results in the highest degree of photobleaching. Furthermore, we set the diffusion constant to the highest value occurring in the presented simulations, namely . The simulation length was (100,000 cycles), and we set the radius and the height of the simulation volume to and , respectively. For , which denotes in how many steps per laser cycle the diffusion and relaxation transitions are simulated, we used eight different values: . In other words, the simulation time step was set to the pulse repetition time of the mode-locked laser and its .