This is because the bad bacteria quickly overcolonizes the effects of Streptococcus salivarius. Those of us with severe halitosis will find that this process will happen much much sooner.
"The NZ lozenge course is 12 doses, whereas the KFORCE course is 32 doses"
I think you should tell the whole truth. The 12 lozenge doseage will deliver 400 million viable cells per day. Since most of the Kforce mouthwash will have to be spat out into the sink and down the drain, I'm going to give Kforce a huge benefit of the doubt and assume that 25% of it remains in the mouth. This already reduces the effective doseage to 8.
I fail to see how 25 million cells (if that) of Streptococcus salivarius per day from Kforce can compete with the already ineffective BLIS lozenges which delivers 400 million viable Streptococcus cells per day.