ABC/HR's scale is as follows:

5.0 = Imperceptible
4.0 = Perceptible, but not annoying
3.0 = Slightly annoying
2.0 = Annoying
1.0 = Very annoying

But in "Subjective Evaluation of State-of-the-Art 2-Channel codecs" by Soulodre et al, which they say was carried out "in accordance with the subjective testing procedures outlined in ITU-R Recommendation BS. 1116", they quote the following scale on the last page of the paper:

5.0 = Imperceptible
4.0 to 4.9 = Perceptible, but not annoying
3.0 to 3.9 = Slightly annoying
2.0 - 2.9 = Annoying
1.0 - 1.9 = Very annoying

So these two scales are the same for Imperceptible, but for anything below 5.0 the two scales are offset wrt to the other by 0.5 (or for pedants, 0.45).

Could someone that has the BS.1116 standard document say which scale they use please?

Thanks.