Endpoints are assigned to Interfaces. An Interface's Endpoints provide the way that the Interface communicates with the PC. The choice of which Endpoint number gets assigned to a particular Interface is arbitrary, and is completely up to the designer of the peripheral device.

The simplest kind of USB devices only have a single Interface.

If you like, HIDmaker FS can easily make devices that have more than one Interface, and therefore more than one set of Endpoints. These are called USB Composite devices.

Usually, the separate Interfaces in a Composite device are used for separate kinds of functionality, like the Printer part of one of those Printer / Fax / Scanner combination devices you see at office supply stores.

However, you can also use extra Interfaces as just different data channels if you want.