I am in the usIt is well known that water companies in the UK make water sound harder than it really is. Your table shows the same trend as UK water companies.
60 ppm is considered soft by fish keepers, not the upper limit of slightly hard. Even 120 ppm is considered soft, albeit at the upper end of soft, while your table says 120 ppm is on the border between moderately hard and hard.
We cannot use water company words for describing hardness as they are in disagreement with fish keeping.
Seriously Fish does give the hardness range for guppies as 143 to 536 ppm. But other very knowledgable members on this forum state that 200 ppm is the minimum guppies should be kept in which is where my information comes from.