Have I got this right?

The run-of-the-mill MTM speaker may have a simple two-way crossover at about 3KHz, both mid-bass drivers receiving the same signal. The concept of two-and-a-half way arrangement means that while one of the mid-bass drivers still receives the full mid-bass range of frequencies, the other mid-bass driver might only come into the mix as the frequencies near 400Hz and lower. As a result, in the two-and-a-half way configuration, the tweeter does most of the work above 3KHz, one mid-bass driver handles most of the work from 3Khz down to 400Hz, and from 400Hz on down, both mid-bass drivers are working.

Sounds ‘pretty nifty.’ I’d be tempted to try it even for vertical use, just to hear the difference and how clarity might be affected - especially if I had three of these across the front, I might want them all in the same mode.