What you write is true, but BC isn't a truly static value, as it is an approximation of flight against some other projectile. As velocity decreases, so does BC, which is why Sierra advertises a BC range for their bullets with a velocity spread. Things always get interesting when crossing the transonic range too.
Some of the VLD designs fly really great until they hit the transonic range, which is why Crane chose the 220 SMK over the 210 VLD when working on the new 300 Win Mag SOCOM load. On paper the 210 has a higher BC and can be driven faster, in reality the accuracy isn't there once the bullet hits the transonic range. I'm really interested to see how Berger's hybrid bullets handle the transonic range as the it would be nice if all the advertising hype is true.