In worksheets with a large number of TM1 functions, DBRW forces TM1 to execute functions in "bundles" rather than individually. Normal DBR functions are executed individually during a worksheet recalculation. DBRW functions force TM1 to execute two passes over the worksheet. In the first pass, all changed values in cells containing DBRW functions are sent in a single bundle to the cube. In the second pass, cube values are sent in a single bundle back to the worksheet. Consequently, the worksheet recalculates twice when DBRW functions are executed.