Solving ODE, simulink vs matlab

Usually, when a set of dynamic equations (nonlinear or linear) are to be solved, we use 'integrator' block in simulink. On the other hand, in MATLAB using ODE solvers, the "myfun" has to be described as a system of differential equations that are of the form dot(y) = f(t,y). Does this pose a chance for numerical errors while solving the equations in MATLAB?

Thanks!