I just finished Tetenals 5l E6 kit, which I mixed in soup quantities of 450-700ml over 1 1/2 years. I measured the concentrates with a measuring pipette, and for my final run the remaining concentrates were only a few ml off. Compared to this your quantities seem way off. Either you received a bad batch, or something went wrong in your measurement procedure ...

BTW: although you have to use three bathes, they call it two bath kit, because they don't count the STAB as bath.