Im always baffled by this... Im confused how some really short and much heavier people than me often claim to be half my size but I assume theres some creativeness in the way they discribe themselves.
Im currently 10.5st at 5ft7 and a size 12-14 (wierdly inbetween these sizes so nothing currently fits right) but im not toned at all so thats mostly fat, when I get more toned I will probably be a stadard 12.
At my smallest I was 7st (clinically underweight) at 5ft7 and because of my bones at my widest points (so hips and shoulders) I was still a 12 but I had tiny boobs and everywhere else mesured a 6-8.
I know people who are barely 5ft clearly look 'curvier' than me, weight 11st and claim they are a size 6-8 and its like 'why lie?' because something just doesnt make sense in that.
Body shape effects things too though, as I mentioned Im 'big boned' so even at annorexic weights my hips bones measure a size 12. My friend who weighed 4st more than me wore size 10 jeans though because she had long skinny legs (5ft9 height) and small hips but she carries ALL her weight top heavy with a bit of a belly and HUGE boobs.
Her top size was wildly different from her bottom size though but I guess if she said she was a size 10 and I was a size 12 then its not a lie.