that is correct according to the above.
according to me, you should size up to 44.
i personally feel that if you are a true, full size 10D , a 43.5 in the U will be very snug. unless you prefer that.
but since you say 9 UK as your equivalent that tells me you prefer a snug fit as i see 9 UK more a 9.5 D US than a 10.
so then 43.5 would be your size in U
according to me, you should size up to 44.
i personally feel that if you are a true, full size 10D , a 43.5 in the U will be very snug. unless you prefer that.
but since you say 9 UK as your equivalent that tells me you prefer a snug fit as i see 9 UK more a 9.5 D US than a 10.
so then 43.5 would be your size in U
