Well, the entire flow through the cell can't be at 80 ppm or that high in FC or else it would come out of the returns that way and require very short on-times. In practice, a properly sized SWG probably outputs at an FC that is about 4 ppm higher than the pool water such that a 2 ppm per day usage would mean roughly 50% on-time during one turnover of the water.
An SWG manufacturer (I think it was PoolSean, but I don't recall) said they measured the chlorine level between the plates at 80 ppm, but not all water flows between all plates. There is some flow around the outside of the plates and water near one plate will be low in FC and high in pH while the other plate will be high in FC and low in pH. It should be noted that the water near the chlorine generation plate is not only high in FC, but in active chlorine level (hypochlorous acid) as well and that chlorine gas bubbles downstream also have a high FC and active chlorine level for a short time until the chlorine is able to combine with CYA (it's fairly fast, but not instantaneous).
So who knows what percentage of water is exposed to high chlorine levels in an SWG cell. Perhaps it's only 10% or less. Basically, The Liquidator operates with an on-time that is longer than that of an SWG -- the LQ is on whenever the pump is on. So since only some of the water flows through the LQ, this means the water leaving the LQ has to be at a fairly high FC, but when mixed with the regular water after the pump the net result is a lower FC than coming out of an SWG. The main difference is that the LQ water has a lower active chlorine concentration lowered by CYA while in the SWG the freshly generated chlorine will be all active for a very short while. But this is all just logical speculation.
Richard