Iteration helps you get a better understanding of a component and its effect on the whole system by changing a certain parameter of it, which might be helpful in designing systems or for learning purposes. Unforetunately, I don’t know about the maximum iteration number possible.
Number of signal blocks generated by each simulation. It mainly affects transmitters and components used in bidirectional simulations and in network ring design. By increasing the parameter iterations a component will repeat the previous calculation until the number of calculations is equal to the iterations.