Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I ordered 4 pairs of moccasin slippers and driving shoes at the same time in UK 11 / US 12, I am probably a genuine UK10 1/2. These were the only pair that didn't fit so as too loose I will try to find some extra fleece in-soles. I would suggest perhaps erring on the smaller side for this one. Shame they were from the US so a simple exchange for a smaller size not possible/practical.