Wptski
Retired Machine Repairman
If the bowl is already full and you add something, it has to force something out which is actually what you stated earlier. If it's already low and you add something, it raises the WL. If you have bucket of water filled to the brim, doesn't putting your arm into make it overflow?It's not what's in the bowl when you get ready to flush, it's the fact that it must be full so the flush action can start things going out as soon as you start. WHen you have to fill the bowl first, it just doesn't work as well and you may end up leaving so mething behind.
That's what I stated earlier, when I urinate without flushing the WL increases. If agree that if I urinate enough, it fill overflow into the drain but I'm unsure if that's the case.
If a Toto's bowl is full to the overflow point that would be more of an issue than my AS Cadet 3.