I've also met CSVs that reached their max height at 15 -18 months. It probably depends on the individual genetic development plan, feeding, etc. etc. Genetics is sometimes tricky and shorter parents may have taller progeny and big parents not necessarily.
The general rule is that young vlcaks that look poorly, i.e. are thin and seem thin-boned usually grow to beautiful wolf-like looking dogs, that move lightly and gracefully, like wolves. Those that look "ready", i.e. adult before they are 2 years old, when fully grown often are too heavy - look and move like GSDs rather than vlcaks.
Besides, the average height of CSV males is about 67,5cm, so 70cm is really tall and looks well only if the dog has a really wolfish body. Otherwise it is heavy and looks good only on winter photos
