For doc blocks, a few small rules:

* Short description, single line break.
* Long description, if needed - double line break.
* @since tag, double line break.
* @uses, @param, @return tags, in that order, single line breaks between them.
* When prefixing classes or functions, use `WPSC/wpsc`, respectively.  When referencing WPeC as an acronym within documentation, use 'WPeC'.  Longform: WP eCommerce.

All that considered, the only changes I'd suggest here is: remove the line break between @uses and @return, and change "is a WPSC tag" to "is a WPeC tag."