Richard,
I don't mean to offend you but it is obvious that you have never worked with or lived with a pool that has a SWG. Chlorine levels will change very slowly with changes in pump run time and cell output...sometimes it can take days for it to stabilize. While you are right that only the water passing through the plates is superchlorinated, in actual practice this seems to be enough to keep the CC at 0 with FC levels that are way below the best guess chart. Also, since algae will first start in the water column before it attaches to the sides and walls of the pool, once again, in actual practice, this seems to be sufficient to prevent algae blooms in normal operation. I view this in the same light as UV sanitizers and ozone generators. Any sanitation only takes place in the reaction chamber and not in the pool proper. The residual chlorine in the water takes care of the rest in all threee of these cases. Perhaps SWGs need to be looked at in the light of this as having 2 separate functions: To generate a residual FC level for the pool and to superchlorinate a small quantity of water in the reaction cell during cell operation to constantly destroy free floating algae and oxidize any nitrogenous compounds in much the same way an ozonator would. As far as superchlorinating all the water, the boost or superchlorinate functions on most units are, IMHO, not really good for this since it can take up to 24 hours to reach the high chlorine levels necessary. I feel it is much more effective to add sodium hypochlorite in the recommeded dosage all at once than to let it gradually climb up. If I understand breakpoint chlorination properly then many undsirable forms of combined chloramines would form at high chlorine levels that are below breakpoint and make breakpoint even more difficult to achieve thus the gradual rise in FC levels by running the celll 24/7 at 100% are not the optimum way to achieve it and may acutally hinder it.
I have only emperical evidence from my own experimentation with my pool but I can tell you this. If I maintain the cya in the 60-80 range and my FC at least 3 ppm and my pH 7.6 or below I do not have any CC nor does the pool ever get cloudy. I have never had an algae breakout since the SWG went online. I have experimented with the above factors and have found that
1. When my CYA is below 60 ppm I have to turn the output up to maintain a 3 ppm FC level.
2. When my pH is above 7.6 I start to show some CC on testing. When it reaches 8.0 my FC level starts to drop.
3. When my FC level is below 3 ppm I have experienced CC and cloudiness of the water.

It is a given that theory often does not hold up in field conditions because of other factors that are not taken into account.

Your thoughts on these points would be appreciated.