Minor
Revert "Round when scaling values"

This reverts commit 10f964623f003c70f6bdd33423420abda3820ce0.

See discussion with Khaled Hosny on mailing list.  In short, since
integers here can be negative, and int division is "round towards
zero", proper rounding should take sign into account.  Just skip
doing it again, has been serving us well before.