In Vukovich v. Radulovich (1991) 235 Cal. App. 3d 281, the court explains that under Code of Civil Procedure section 632, "it is for the trial court to determine what are the 'principal controverted issues'--those on which the outcome of the case turns. 'The law is well settled that if findings are made on issues that determine the case, other issues become immaterial and a failure to make additional findings does not constitute prejudicial error .' Citation. " (Vukovich, supra, 235 Cal. App. 3d at p. 295.)