I am understanding the method correctly? Do you switch to bleach and never use Dichor again, as you stated "one switches to using bleach"
In addition to what chem geek said, you would also restart the cycle with dichlor/trichlor each time you drain/refill the spa, since the fill water would have zero CYA.
Edit - jblizzle already said that... um... yesterday. Never mind...
Also, would it make sense to add a liquid or powder stabilizer, such as Cyanuric Acid (CYA) with bleach instead of Dichor? I would think with liquid or powder, you would have more control.
That seems to be the most common recommendation you see here for pools -- add CYA separately and use only bleach -- but dichlor/bleach works really well for spas where the volumes are lower. Dichlor is also handy because it dissolves quickly, which is nice if you drain/refill regularly, although since I started using the dichlor/bleach method I find the water stays nice and clear for months at a time.
Dichlor is a powder (ok, "granules") so you can add a measured amount and calculate how much CYA is going in, and in principle you can keep track of how much dichlor you're adding and switch over to bleach after you have added the amount of dichlor which raises your CYA to the right level.
The trichlor/bleach suggestions are just a way to help you make good use of the tabs you already have. I guess the same idea could work, where you count the number of tabs you add and switch to bleach after the right number, but testing CYA level is still a good idea. The nice thing about stabilizer/bleach or dichlor/bleach or trichlor/bleach is that normally the CYA level doesn't change much after you switch to bleach so you don't need to be frequently testing CYA levels and tweaking target FC levels to match.
Makes things really easy, even for me