Xbee API mode - Is radio baud the same as link baud?

Not quite sure how to phrase this best so please bear with me.

Is the baud rate used to communicate between the microcontroller and xbee the locked (or linked) to the over the air link transmission speed? Theoretically with API mode, the xbee could buffer the communications and operate over the air at a different speed to the interface to user microcontroller. This matters because the over the air rate has impact on transmission quality and distance but a highish baud to microcontroller can make systems smoother.

Appreciate and info or links that clarify this.