Image Quality issue with script

Question

So I recently wrote a simple script to output an image at a bunch of different resolutions. However, I am running into an image quality issue that I don't run into when I do the same thing manually.
Here is an example image showcasing the image: http://terminalvelocity.ca/temp/notworking.jpg
As you can see along the top of the model's forhead there is destinct color fragmentation. Which seems very strange.
Here is the script, it is pretty simple, it asks for a few simple config options. (the above image was created using default settings). It then figures out the correct ratios and loops through doing each resize, saving the image, then reverting the history so each iteration uses the original image data and not the resized version:
doc = app.activeDocument;
openFilePath = Folder.selectDialog ("Where do you want the images to be saved?");
maxSize = Number(prompt("What would you like to be the maximum length of the long edge? (Image is never upsized) (pixels)", 2800)); 
minSize = Number(prompt("What would you like to be the minimum length of the long edge? (pixels)", 100));
gap = Number(prompt("How much smaller should each image be? (pixels)", 100)); 
quality = Number(prompt("What quality would you like the JPG exported as (0-12)", 10)); 
var size;
var primary;
var secondary;
if(doc.width > doc.height){
          primary = doc.width;
          secondary = doc.height;
}else{
          primary = doc.height;
          secondary = doc.width;
var ratio = secondary/primary;
var size = [];
for(var i = maxSize;i>minSize;i-=gap){
          var  p = i
          var s = i * ratio;
          size.push([p,s]);
var w;
var h;
var n;
for(var i in size){
          if(doc.width > doc.height){
                    w = n = size[i][0];
                    h = size[i][1];
          }else{
                    w = size[i][1];
                    n= h = size[i][0];
          if(doc.width >= w && doc.height >= h){
                    doc.resizeImage(w,h,null,ResampleMethod.BICUBICSHARPER);
                    jpgFile = new File(openFilePath+"/"+n+".jpeg" )
                    jpgSaveOptions = new JPEGSaveOptions()
                    jpgSaveOptions.embedColorProfile = false
                    jpgSaveOptions.formatOptions =
                    FormatOptions.STANDARDBASELINE
                    jpgSaveOptions.matte = MatteType.NONE
                    jpgSaveOptions.quality = quality
                    app.activeDocument.saveAs(jpgFile, jpgSaveOptions, true,Extension.LOWERCASE);             
                    doc.activeHistoryState = doc.historyStates[doc.historyStates.length-2];
In comparison, here is an example of an image of the exact same resolution that does not exhibit this issue at all:
The steps taken to save this image were as follows: http://photography.terminalvelocity.ca/content/images/2012/avery_konrad_6/horizontal/1500. jpg
Image > Resize > Bicubic Sharper (1500px);
Save For Web
     Jpeg
     Quality 75
     Optimzed: true
     Progressive: false
     Blur: 0
     Convert to sRGB: true   
Anyway, as you can see, The manually exported image does not have any of the quality issues that are present within the scripted image. I am pretty new to photoshop scriping so am assuming it has something to do with me missing some sort of option in the save settings. Any help would be swell.
Also note, this doesn't occur on all images, I usually don't see an issue when using the script, however, something about the tones of this particular photo make it really obvious.
I am using the latest version of Photoshop CS6 (creative cloud) on Max OSX
thanks so much!

Answer 1

I'm on windows find the bicubicsharper does not work well it the image being resized has been highly sharpened all ready. Because of my Photoshop preferences I had to make minor modification to your script. I'm also a bit colorblind so i don't see many color issues so I include a screen capture if what windows does with your image and script.
var orig_ruler_units = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;          // Set the ruler units to PIXELS
doc = app.activeDocument;
openFilePath = Folder.selectDialog ("Where do you want the images to be saved?");
maxSize = Number(prompt("What would you like to be the maximum length of the long edge? (Image is never upsized) (pixels)", 2800));
minSize = Number(prompt("What would you like to be the minimum length of the long edge? (pixels)", 100));
gap = Number(prompt("How much smaller should each image be? (pixels)", 100));
quality = Number(prompt("What quality would you like the JPG exported as (0-12)", 10));
var size;
var primary;
var secondary;
if(doc.width > doc.height){
          primary = doc.width;
          secondary = doc.height;
}else{
          primary = doc.height;
          secondary = doc.width;
var ratio = secondary/primary;
var size = [];
for(var i = maxSize;i>minSize;i-=gap){
          var  p = i
          var s = i * ratio;
          size.push([p,s]);
var w;
var h;
var n;
for(var i in size){
          if(doc.width > doc.height){
                    w = n = size[i][0];
                    h = size[i][1];
          }else{
                    w = size[i][1];
                    n= h = size[i][0];
          if(doc.width.value >= w && doc.height.value >= h){
                    doc.resizeImage(w,h,null,ResampleMethod.BICUBICSHARPER);
                    jpgFile = new File(openFilePath+"/"+n+".jpeg" )
                    jpgSaveOptions = new JPEGSaveOptions()
                    jpgSaveOptions.embedColorProfile = false
                    jpgSaveOptions.formatOptions =
                    FormatOptions.STANDARDBASELINE
                    jpgSaveOptions.matte = MatteType.NONE
                    jpgSaveOptions.quality = quality
                    app.activeDocument.saveAs(jpgFile, jpgSaveOptions, true,Extension.LOWERCASE);            
                    doc.activeHistoryState = doc.historyStates[doc.historyStates.length-2];
app.preferences.rulerUnits = orig_ruler_units;          // Reset units to original settings