Why custom.css is NOT loaded as the last css file ?

In the Customize template with CSS part of T3 Framework documentation, you mentioned that:

Some characteristics of the custom.css file
...
The file is the last file to be loaded in your site.

Well, in my test of T3 v2.5.0 on Joomla 3.4.3, I noticed that the file custom.css was NOT loaded as the last one in HEAD part.

Could you please check this and fix it?

Thank you.