Why do I have to run a doc.saveAs() prior to Inserting, Deleteing, or Extracting pages?

Question

MY SETUP:
I'm using folder level javascripts.   In Acrobat I have the 'enable menue items javascript execution privledge' enabled,  In my actual folder level scrips I have them wrapped in a trusted function along with app.beginPriv()/app.endPriv().    My PDF's are coming from LiveCycle Designer which I then open and run in Acrobat.
MY QUESTION:
Through much trial and error and banging my head on the wall I've found that if I want to use insertPages(), extractPages() or deletePages() called as a trusted fucntion  on its own it won't work unless I first run a saveAs() function to create a new document file and only then can I run the desired function on the new saveAs'd doc.   I simply can't run an insertPages() on the current open doc without a saveAs first().    
Why is that?
I find that very frusterating and the resulting errors aren't a help.  If I don't SaveAs first I get security error or invalid function errors.
EXAMPLE:
Save As Function:
var LCB_SaveAs = app.trustedFunction(function(doc, filename) {
    app.beginPriv();
    doc.saveAs(filename);
    app.endPriv();
Insert Page Function:
var TEST_InsertPage = app.trustedFunction(function(doc, filename) {
    app.beginPriv();
       doc.insertPages ({
           nPage: -1,
           cPath: filename
       app.endPriv();
Javascript code in document to call the above functions:
if(typeof(LCB_SaveAs) == "function") {
    if(typeof(TEST_InsertPage) == "function") {
        try {
            TempFileLocation = "/C/PATH/InsertTemp.pdf"
            LCB_SaveAs(event.target, TempFileLocation);
            try {
                PathOfInsertDoc = "/C/PATH/FileToInsertIntoSaveAs'dDoc.pdf"
                TEST_InsertPage(event.target, PathOfInsertDoc)
            catch(e) {
                xfa.host.messageBox(e.toString().replace("RaiseError: ","") , 0, 0); 
        catch(e) {
            xfa.host.messageBox(e.toString().replace("RaiseError: ",""), 0, 0); 

Answer 1

Hi George.  Yes I'm using static XFA forms which were created with PDF's as basic 'artwork' in the background and then my custom fields and script tunning on top. 
I've tried running  a function (below) in the console, but did nothing -- maybe a syntack error.  I don't know what that may or may not mean though.  I'm not use to running stuff through the console so I could be doing it wrong.  My console experiance is limited to calling the path where the javascripts folder resides.
Attempt script in console:
var MJS_HN_Delete_RevisitForm = app.trustedFunction(function(doc) {
    app.beginPriv();
    doc.deletePages(15, 15);
    app.endPriv();
and/or this:
app.trustedFunction(function(doc) {
    app.beginPriv();
    doc.deletePages(15, 15);
    app.endPriv();