How to set font size with Extendscript

I am trying to set the font family, size and style of the selection using ExtendScript. Family and Style are applied correctly but the font size stays the same. FM2019. What am I doing wrong?

FA_Errno  is set to FE_Success after the operation.

function fixText(targetDoc){
var i = 0;
   var arial = GetFontFamilyValue("Symbol"); 
   var textProps = AllocatePropVals(3);
    i=0;
    textProps[i].propIdent.num = Constants.FP_FontFamily;
    textProps[i].propVal.valType = Constants.Integer;
    textProps[i].propVal.ival = arial ; 
   
    i++;
    textProps[i].propIdent.num = Constants.FP_FontSize;
    textProps[i].propVal.valType = Constants.Integer;
    textProps[i].propVal.ival = 36 * 65536;
     
    i++;
    textProps[i].propIdent.num = Constants.FP_Underlining;
    textProps[i].propVal.valType = Constants.Integer;
    textProps[i].propVal.ival = Constants.FV_CB_SINGLE_UNDERLINE;
   
    var  tr = targetDoc.TextSelection;
      targetDoc.SetTextProps(tr, textProps);
      PrintFAErrno ();
      return;

     }