Another point is that they have different basics. The motion for the double-factor block as a block is different than the motion for double-factor block as break. Having vaguely the same motion is not the same as having the exact same motion, especially when forms are all about perfecting even the little details. Doing Short 1 with the fancy moves actually changes the form, in minor ways, throughout. Again, a useful exercise for advanced students, but it's not really Short 1 anymore. It's a modified Short 1, with grabs instead of chambers, buckles instead of efficient transitions, and so forth. Probably depends on how precise and detailed a person insists on being with the forms to begin with.
I'm not even sure how this fits into the argument, but I thought I should mention it.