Dave, I absolutely approve of your idea. Teachers are instructed to provide students with the actual interlocking cubes when learning this concept. I do not understand the need for the braille reader to transfer that 3-dimensional tactile experience with a tactile graphic on the page. Sighted students look at those diagrams and think "100" or "10" or "1," they are not counting each block. We are slowing down our students' ability to enjoy this same experience by creating unwieldy graphics out of these -- some of which can take up several pages.
However, the warning must be understood that, once we have a BANA rule or guideline for specific items, this is how they will be produced on the standardized tests. We do our students a disfavor when we do not follow those guidelines in their daily work. I do think this topic of grouped counting cubes needs to be reassessed.