there’s a fair chance you’ll get anywhere between 55 and 65 (though in fairness there’s about a 2 in 3 chance of getting 59,60 or 61)
Presumably they only care about weight - and also presumably carefully control that, to avoid giving too much candy*, which suggests the individual candies vary in size/density quite a bit.
*Although, alternately, this might just mean that 65-ish candies is the target and they consistently shortchange buyers.