For Reference: Shrink Item
Note:So in the debate a tenth level wizard is casting this spell to get the required 20 cu. ft. Correct?Target: One touched object of up to 2 cu. ft./level
The measurement of Cubic feet is one of volume in can be annotated as ft3 or as cu. ft. both refer to the space inside a 3 dimensional figure. Since the distance is not measured in feet, for example Fireball, it already is a measurement of volume.
In short: The first interpretation (i.e. 20 1-ft cubes in any configuration) is the correct one.