Boots throat lozenges: when 24÷3=12

Spotted on the back of a packet of Boots own-brand throat lozenges:

Adults and children over 6 years:
Suck one lozenge.
Dissolve the lozenge slowly in the mouth.
Repeat this dose every 3 hours, if needed, up to a maximum of 12 lozenges in 24 hours.
Do not exceed the stated dose.

I'm not a maths genius, but I do know that 24÷3=8. So why warn people not to exceed 12 lozenges in 24 hours?

And if people are going to disregard the first part of the instruction ("Repeat this dose every 3 hours, if needed"), what makes Boots think they will pay heed to the second part ("a maximum of 12 lozenges in 24 hours")?