Trying to use app.execMenuItem("Save"); to save a file and having problems

Thank you for that guidance. Copying and pasting from the page you linked to, I changed my code to this:

app.addToolButton({cName: "MyFlattenButton",
cLabel: "Flatten",
cTooltext: "Flatten all pages",
cEnable: "event.rc = (app.doc != null);",
cExec: "saveandflatten();"
});

var Trusted_MyDocSave = app.trustedFunction(function(oDoc)
{
app.beginPriv();
oDoc.saveAs(oDoc.path);
app.endPriv();
});

function saveandflatten() {
Trusted_MyDocSave(this);
this.flattenPages();
return 0;
}

This seems to operate correctly now. I also added the Acrobat Javascripts folder as a trusted location in the Enhanced Security preferences window (was that necessary?). 

But now a new question -- sort of a long explanation but wondering why this occurs:

- My original need to add the save feature to this script is due to some bug in either Acrobat or my CAD software. When I create a PDF directly from my CAD software (Bricscad) it is faster to do it using the Bricscad-supplied create PDF feature rather than printing to Acrobat. But then if I open the file in Acrobat and add a stamp (which I often do) and then flatten the stamp (for security) it messes up all the fonts in the PDF. The workaround is to add the stamp, save the PDF, then flatten. That works fine for some reason.

I reported this bug to Adobe and to Bricscad but neither could solve it. So I thought why not just incorporate the save into my flatten routine. But when I do that and run the code above (which appears to operate correctly) the fonts get messed up as if the save did not happen. I tried commenting out the flatten code in the script to be sure the save was happening and it appears that it was being saved. 

Is something different happening in the script than when I do this manually? I tried manually using Save As before flattening and that works fine (no messed up fonts).