PNG creation with modified date

HI,

The following steps are doing.

1) Open two indesign files. One is source and another one is final file.

2) Based on modified date I need to create the png with file naming as _source and _final.

mains();  
function mains() {      
    var docSou = app.documents[0]; 
    var docFin = app.documents[1]; 
    var SouName = File(docSou.fullName);   
    var FinName = File(docFin.fullName);  
    var modifiedDate1= SouName.modified;  
    var modifiedDate2= FinName.modified;  
    
    mycheck1();
    
    function mycheck1(){
        if(modifiedDate1<modifiedDate2){
            var docName =docSou.name.replace(/\.[^\.]+$/, '_source');
            set_png_export_options();  
            var file = new File("~/Desktop"+"/"+docName+".png");              
            docSou.exportFile(ExportFormat.PNG_FORMAT, file);  
            mycheck2();
            exit();
        }
        else{
            var docName =docFin.name.replace(/\.[^\.]+$/, '_final');
            set_png_export_options();  
            var file = new File("~/Desktop"+"/"+docName+".png");  
            docFin.exportFile(ExportFormat.PNG_FORMAT, file);  
            mycheck3();
            exit();
        }
    }
function mycheck2(){
    var docName =docFin.name.replace(/\.[^\.]+$/, '_final');
    var file = new File("~/Desktop"+"/"+docName+".png");  
    docFin.exportFile(ExportFormat.PNG_FORMAT, file);  
    }
function mycheck3(){
    var docName =docSou.name.replace(/\.[^\.]+$/, '_source');
    var file = new File("~/Desktop"+"/"+docName+".png");              
    docSou.exportFile(ExportFormat.PNG_FORMAT, file);  
    }
}  
  
function set_png_export_options() {  
    with(app.pngExportPreferences) {  
        antiAlias = true;  
        embedColorProfile = true;  
        exportResolution =  1600;  
        exportingSpread = true;  
        PNGColorSpace = PNGColorSpaceEnum.RGB;  
        PNGExportRange = PNGExportRangeEnum.EXPORT_ALL;  
        PNGQuality = PNGQualityEnum.MAXIMUM;  
        simulateOverprint = false;  
        transparentBackground = false;  
        useDocumentBleeds = true;  
    }  
}  
   

But it always show the first document as _source.

Could you please suggest where I am missing.

Regards,

K