These grading systems refer to both the peroxide and non-peroxide activity of the honey. Because of the quick degradation of hydrogen peroxide antibacterial activity when exposed to fluids (i.e. saliva), heat, and sunlight this is not an ideal measurement.
Avoid honeys that are labelled with ‘Active’ or ‘BioActive’. These labels are misleading and are unlikely to offer any of the antibacterial benefits Manuka honey is known for.