Simple Resizing Script - Hopefully better eyes will prevail

Question

     I'm working on a simple resizing script to incrementally resize an image in 5% steps up to the set limits as defined by the variables; newImageHeight & newImageWidth.   I'm currently running this script in Photoshop CS4 on an Intel Mac.
     The script works fine for horizontal format images but vertical images scale incrementally in significantly larger steps than 5% and the final output is well above the limit set by the variable "newImageHeight".
     I'm sure it's something simple that I've just overlooked.  Any help would be most appreciated.
TIA
#target photoshop
//  Sets Adobe Photoshop to use pixels and display no dialogs.
app.preferences.rulerUnits = Units.PIXELS;
var doc = app.activeDocument;
var imageFormat;
var newImageHeight = 4000;  //  Sets the new image height to 4000 pixels.
var newImageWidth = 2880;  //  Sets the new image width to 2880 pixels.
if (doc.height.value > doc.width.value){  //  Determines whether the image is vertical or horizontal in format.
     imageFormat = 1;
     }else{
     imageFormat = 2;
if (imageFormat == 1) {
     alert("Re-Scale Portrait Format");
     while (doc.height.value < (newImageHeight * 0.923550372529964)){
          alert(doc.height.value);
          doc.resizeImage (doc.height * 1.05), ResampleMethod.BICUBIC;
     alert(doc.height.value);          
     doc.resizeImage (doc.height * (1 / (doc.height / newImageHeight))), ResampleMethod.BICUBIC;
     }else{
          alert("Re-Scale Landscape Format");
          while (doc.width.value < (newImageWidth * 0.923550372529964)){
          alert(doc.width.value);
          doc.resizeImage (doc.width * 1.05), ResampleMethod.BICUBIC;
     alert(doc.width.value);     
     doc.resizeImage (doc.width * (1 / (doc.width.value / newImageWidth))), ResampleMethod.BICUBIC;
//  EOF

Answer 1

Check resizeImage out the Object Model Viewer in ESTK.
Document.resizeImage (width: UnitValue , height: UnitValue , resolution: number , resampleMethod: ResampleMethod )
So I think the line
          doc.resizeImage (doc.height * 1.05), ResampleMethod.BICUBIC;
should rather be
          doc.resizeImage (doc.width * 1.05, undefined, undefined, ResampleMethod.BICUBIC);
or
          doc.resizeImage (undefined, doc.height * 1.05, undefined, ResampleMethod.BICUBIC);
What is the Script supposed to achieve anyway?
It’s not based on the obsolete concept of incremental resizing for better results, is it?