The only circumstances where you might not be able to use the Maximize function for a self-employed 401(k) contribution is if you made employee elective deferrals or Roth contributions to a 401(k), 403(b), federal TSP of a SIMPLE plan at another employer. In that case you need to limit your elective deferral to the self-employed 401(k) so that the combined employee elective deferrals and Roth contributions do not exceed the limit for your age.
