Question about propt optimization code

Hello everyone. I have found the following example in which a version of Zermelo's optimization problem is solved. There is however a part of the code that I don't understand:

The first two lines of the document are:

% Array with consecutive number of collocation points
narr = [20 40];

and later on, the author writes

% Initial guess
    if n==narr(1)
        x0 = {tf == 2; icollocate({x1 == xi(1); x2 == xi(2)})
            collocate({u1 == pi})};
    else
        x0 = {tf == tfopt; icollocate({x1 == xopt1; x2 == xopt2})
            collocate({u1 == uopt1})};
    end

and

    tfopt = subs(tf,solution);
    xopt1 = subs(x1,solution);
    xopt2 = subs(x2,solution);
    uopt1 = subs(u1,solution);

If I understand propperly, the code first constructs an optimal solution based on a very simple guess and then, uses the found optimal solution as an initial guess for a second optimal solution?

If someone can confirm that I have undestoood this correctly, I would be very thankful.

Regards.

Jaime.