Code Size

Why is there such a large difference in code size between what is reported in the map file and what is displayed in the download window of the IDE? For example, according to the map file for my application my code size is 89866 bytes (sum of root code and xmem code). Yet, when I compile-to-target, the IDE reports the total amount of code to download is 259712 bytes. Is the difference attributed to the Rabbit BIOS, or what?