Okay think of the flash memory like this. Whenever you save something to flash it is stacked in there on the next available page. So if you save 1 app, it will be saved on the first available page. If you have a second app it will be stored on the second page. but if you deleted the first page, it is not actually deleted, but marked as deletable. Then when you have reached your limit of flash TIOS goes in and deletes the deletable pages to make more room at the top.