best practice to build the existing applications with sencha cmd?

I use the extjs 4.2.1 as the front-end framework. When I finished the developing stuff, I have to prepare for the release. I knew later that there is a specific tool provided by sencha itself which support functionality like compressing js files, but i did not develop in the expected way(i did not use the command like sencha generate app test and so on), consequently it seems that i will not benefit from the sencha cmd. So, i wonder what is the best practice like this? there is a very important feature in extjs4.2.1 --- the dynamic loading, the official documentation has a note on that when deploying the application which is as below: Deployment

It's important to note that dynamic loading should only be used during development on your local machines. During production, all dependencies should be combined into one single JavaScript file. Ext.Loader makes the whole process of transitioning from / to between development / maintenance and production as easy as possible. Internally Ext.Loader.history maintains the list of all dependencies your application needs in the exact loading sequence. It's as simple as concatenating all files in this array into one, then include it on top of your application. This process will be automated with Sencha Command, to be released and documented towards Ext JS 4 Final. So, is there some post on this topic? I feel confused that why the dynamic loading could not be used in the production development?