By the way, I know this pipe operator became fashionable. However not only does it make the code less obvious than it could be, but in general if you write your divisions that way it increases the chances you won’t benefit from OCaml’s float unboxing (you won’t if the function doesn’t get inlined).
I don’t really see what is wrong with writing:
let round2 n = Float.round (n *. 100.) /. 100.