Size of 1607 Win 10 MCT download

I downloaded through the Media Creation Tool for a friend and the resulting file was to be burned to a cd.
That resulted with an error after the burn completed with the Windows Explorer burn.
The total file is 3545472 which I translate into 3.5Gb
Attempts at creating a Rufus boot usb did not display the 'use Windows standard' ( or to that effect) when I linked to that .iso. Since it did not look exactly like the samples in the Tenforum tutorials I backed out and decided to do a double check.
My own download in Aug for the 1607 version was 4.2Gb (4277722kb)
Meanwhile it takes hours for these downloads and I'm downloading again but not with the MCT
Is the current iso downloading any different in content from the Aug AU update?
The goal is to do a clean install on the friend's laptop. He had no success upgrading to the AU version from 1511 so went back to Win7

Well that 3.5 total download had to be faulty because I just ran the Rufus tool on my original Aug 1607 download and immediately the words Standard Windows Installation showed up and its ready to do its thing on a USB flash drive.
So my friend will just have to do a bunch of updates to catch up.

The ISO file is the same as the August AU. Microsoft usually does not update the ISO file between major builds and the next major build is scheduled sometime in early 2017.

Right. I am now using my original download and the Rufus tool is immediately doing what is expected.
Once this install is complete on the friend's laptop he can do his own updates from Oct and Nov.

I have never had a bad download before but I usually go to the catalog. Sort of ironic that the MCT routine for burning to a cd resulted in loss bits.