Having Trouble with Javascript and Smart Forms

For the life of me I can’t figure out why I’m unable to update a field value before submitting the form. Although my Javascript validates I am unable to see the changed field value in the entries screen. I’m sure it’s something simple but if you could please review and tell me what I’m doing wrong (or where to look for an answer) it would be much appreciated:

BeforeFormSubmit:function(formData,jQueryFormReference){
    //Here you can put code that you want to be executed before the form is submitted
  var vEmailto = jQuery('#rnField10');
  var vPickvalue = jQuery('#rnField3');

   switch (vPickvalue.val()) {
      case 1: vEmailto.val("email@site.com"); break;
      case 2: vEmailto.val("email2@site.com"); break;
      default: vEmailto.val("email3@site.com");
   }
}

https://wordpress.org/plugins/smart-forms/