Pain of IntelliJ IDEA upgrade: Why this way?

I have read many posts supporting IntelliJ IDEA and lots of it's good features. Inspired by these posts I've decided to work with IntelliJ IDEA. I have IntelliJ IDEA 6.0.1 installed. So far so good. But when I run my IDE, it has come up with the upgradation information that new version 6.0.4 is available. See the dialog:



When I click the Updates link, then another dialog will open :


This is all about the settings of upgrade option. That's good. I'm quite happy with that. But first of all, I don't find any express upgrade option. It's even ok. I will upgrade manually. I click "More Info..." button to upgrade manually and I expect only the upgrade not full download of the IDE. But clicking that button will open the JetBrain site to download the whole package.



I don't have any option to download only the upgrade. I have to download the whole 65.7 MB, again install it and provide the license. One thing I don't understand that why the upgrade process of such leading Java IDE is so tedious. As far as I know the versioning convention of any well established software is like XXX.YYY.ZZZ where XXX is the major version number, YYY is minor and ZZZ is Bug fix or some patches. So if we see this convention the upgrade option of IntelliJ IDEA is nothing but Big Fix or Patches. Why I go for the full installation or download for only the patches? Can anybody tell me the actual working or I'm wrong?